B&W Nautilus 803 or B&W 702 S2?

I'm currently sporting Paradigm 60 v3 for my fronts and considering purchasing B&W Nautilus 803 that are 10 years old or purchasing new B&W 702 S2.  My room is 25 x 20 feet, using Anthem A5 currently with McIntosh 135. Which would be a better fit based on these specs...and am I better off keeping the Paradigm's?
Of the 2 B&W Options my pick would be the new 702 S2. I would also pick them over your Paradigms. If you haven't listen to them be sure and do so first to make sure you like them more than your Paradigms. 

Neither, to enjoy the B&Ws you must have an amp that at least double downs from 8ohm to 4ohm and preferably if you can afford if further doubles down to 2ohm.  Both sets of speakers above dip as low as 3.7ohm and spend a lot of their frequencies between 4-6ohm.  You'll be very disappointed driving them with Anthem A5, the result would be lean and bright sound.  I'm giving feedback based on my personal experience using up to Parasound Halo Integrated to drive B&W 805S.

 As shameless self advertisement, if on a budget you should consider something like the ClassDAudio amp that I'm posting for sale or something like the Marantz HD-AMP1.

But if you must choose something, I'd say pick the latest 702 S2 and it can perform at 80% of the latest 804 D3 (admittedly, in hifi that remaining 20% can be really big deal).  The 803 Nautilus is at least 20yrs old technology, the new 702 S2 is leap and bounds ahead catered to modern digital high resolution music.  But if you're more the analog and tube kind of guy not into high resolution digital, go with 803N for warmer sound.  I have both 805S and 805D3.

Thanks and I appreciate your food for thought. We do a lot of both digital and vinyl but I should also mention that this system doubles as our home theater. The Anthem A5 has been a concern of mine as well, I have my sights in on Mcintosh MC205 which I think will meet the needs from what I understand. What are your thoughts about 803s/804s or 803d/804d? I believe those are slightly newer? I will be auditioning 702 s2’s and CM series tomorrow, along with the rest of B&W line.
All the D series B&W's are more efficient than the older N and S models. One of my favorite systems I sold to a client of mine was the 802D2 on a ARC Ref75 which powered them just fine. I do agree somewhat with hifineubee that the S and N series B&W needed series power in order to make them really sing properly which is why I mentioned my choice of the 702 over the N803. Your current A5 will do just fine powering the 702. 
I was able to audition 804d3's today and they were very nice, but we also listened to Focal Kanta 2's and they were especially nice.  They also have a pair of Focal Electra 1038's that we were unable to audition, but from what the rep we telling us they are even better than the Kanta's...not sure though, from what I read Kanta's were replacing the Electa's.  Wondering how my Paradigm Reference Studio CC-570 V3 center would pair with either of these?
Hi, not too sure how to advice you.  Your demo journey has far exceeded the original price range of what you're looking for.  When you hit $10k range, those speakers tend to be super picky with what gear you're pairing with, break in time, speaker cable used, music source...etc.  Listening to my 805D3, different recordings of the same song sound significantly different.  Try listening to old vinyl, vs 44khz CD, vs DSD vs complete remastered 192khz FLAC and you'll see.  Without a good grasp of what your true budget range is, give your existing gear budget range, it would be very unwise to use such high end speakers for both music and hifi listening purpose.  Most typical AV receiver are all unable to properly power such speakers.  Most cannot do 4ohm let alone less than 4ohm.  Your resulting experience will be very lean sound.  Otherwise, you'll need to shell out a lot of money to add a secondary amp(s) to power your large speakers besides using AV receiver.  Then you'll have all the other components to add.

As for the other B&W speakers, they're all very different.  803D is a lot bigger in size than 803S.  D1/D2 has diamond tweeters vs S's aluminum tweeters.  While both D and S line have kelvar woofers (the yellow cone), they are also tuned to have different sonic signatures (though not obvious unless you've owned them all like myself, I started with 805N).  In general, I can say from personal experience, diamond tweeters are not the wow thing their price would suggestion.  Better yes, but not 10x different as reflected in replacement parts cost.   In general, each B&W 800 series generation loses warmth, become more neutral and more high resolution sensitive.  Based on demo experience, the new continuum woofers used in 800 series D3 and 700 series S2 pair very well with Mcintosh amps.  I will also add that personally I don't think neutral is a good thing, when today's new speakers, amp, cables, DAC are all 'neutral', what you get is the most blend sound ever, like eating organic salad with no flavoring or dressing.  So beware.
Hi hifineubee, how do the 702 S2 compare with the 805 D3? assuming they are driven by a good amplifier like the Bryston 4B3 300 watts, 24/96 or vinyl?   I know not properly driven both are very hard speakers to drive, they sound thin, edgy, dry, narrow mid range, like any under $500 speaker. I don't know how they may sound with a tube amp.  I have a 70 watts integrated tube amplifier and soon want to auditioning the 805 D3 on my house.  I'll post my findings when I listen them. 

Hi judgmentday, great questions you have there.  I have some great answers for you that'll hopefully save you tons of money mistakes that I made.  I'll just ask that you bare with my answers below with some patience and an open mind.

First off, speakers are not driven by watts, they are driven by electric current.  I learnt to understand this the expensive way, buying t a $2500 Parasound Halo Integrated and couldn't for the life of me understand why my 805S sounded so poorly.  Keep an open mind here, cause this is where I'm going to help save you tons of money.

Now some quick important facts about the two B&W speakers you asked about.  I would definitely take the 805D3 over the 702 S2 because I love the high detail resolution and the 'special' spec that the 805D3 is the only B&W with a 4.7ohm minimal impedance.  This is very important because this makes the 805D3 compatible with most Class AB & D amps that cannot push low 2-4 ohm impedance.   702 S2 is awesome on its only at $4500 a pair vs the 804 D3 at $9000 a pair.  If you're willing to give up resolution in exchange for the fuller sound of a full tower, 702 S2 is very good in its price range, awesome if you get it used around $3000 range.  Note that 702 S2 has a carbon tweeter not diamond tweeter.  Note that you must break in the 805D3 for at least 120hrs based on my experience and brace yourself for some really lean and bright sound the first 60 or so rollercoaster hours.

The 805D3 loves solid state and tube amps equally.  First of all, I would recommend you hold off on Bryston amp unless you already have it.  You want an amp that does 1.x 8ohm and 2.x 4ohm, the Bryston is only 1.6x at 300W 8ohm and 500W 4ohm.  Without going into science details, the Bryston 4B3 is not generating electric current across a wide enough impedance to keep the B&W happy.  Here's where I'm going to save you money.  As alternative, try

For solid state, Marantz HD-AMP1.  The meager spec will shock you what 35W 8ohm 70W 4ohm with Marantz current feedback feature can do.  I have a 16x13x8 room and I cannot play at even half volume with this amp.  You can get this from Amazon and return within 30days.  Once you try this, you'll forever change perception of amplifier specs.

I tried 805D3 with a chinese Yaqin EL34 push pull amp and it worked well though I didn't really get the warm and fuzzy tube sound.  Currently I'm using a 8W 300B SET amp with the 805 D3, works ok with female vocal, jazz...etc small music.  In general, I use 300B SET when I want that holographic voice whispering in my ears feeling and the Marantz for large soundstage orchestral music.

Currently I confess I am still not driving the 805D3 with good enough gear, when I have the money, I would invest in a Mcintosh which I feel is closet to best of both tube and solid state worlds.  If you can afford, you should try demoing the B&Ws with a Mcintosh MAC6300 or higher model with autoformer.

Did you ever end up picking a pair of speakers? Interesting thread as I keep going back on forth on the same issue. I heard the 702 s2 and really liked them. I think they are very good for the money. Something keeps me wanting the d3 series instead but really not sure for me if its worth the extra money.
Im a newbie to the world of audio so forgive my lack of correct lingo and understanding of it. :-)

I used to have a pair of b&w cm10 s2 paired with  a intergrated amp rotel ra-1570 I bought 2 years ago & Chord 2qute dac until one speaker was damaged .  

I was sent a replacement set of the b&w 702 s2 without having ever heard them . Now I realize what an amplifier does and the difference between them and intergrated amps! Yikes 🤦🏻‍♀️ 

So now im wondering where do I go from here ? I thought the speakers sucked until my friend hooked them up to a class a amp and a Velodyne DD18subwoofer . So QUESTION IS .. 
What kinda power amp can I buy to power these 702 s2's without killing my piggy bank? Had no idea audio equipt was so so complex ! 
I'll put a couple suggestions that have already been recommended a lot.  The Hegel H160 will be a better and more refined integrated than the Rotel for about $1600-1900 used.  The H300 will be better than that, as the B&W speakers really need a high current / high power amp.  Other options could be the older generation Emotiva amps with a fuse upgrade (such as XPA-1 gen 1, or any of the XPR series).   Parasound A21 would also be a nice amp, and also works great with fuse upgrades.
I highly recommend a tube preamp partnered with a Wyred for Sound ST 500 amp.  I have B&W N802 and Concept 90 speakers.  This combo is killer on both pairs.  
Beware of all the hearsay recommendations from people that don’t own B&W speakers.  My 2 cents.
Hi  chief4425, I ended up holding off on speakers for the time being and decided to put my efforts into upgrading the amp.  I went with a used McIntosh Mc205, got it in May.  It sounds amazing and couldn't be happier.  I still have the old Paradigm 60 v3 - have had them for 15-16 years.  I can't believe how great they sound and can only imagine what a properly chosen speaker(s) will be like.  We will be going to the RMAF (Rocky Mountain Audio Fest) this weekend and will be looking at several speakers.  Anyone have any suggestions on speakers other than B&W, Focal (I plan on those already, along Zu Audio, and Tekton)  Any suggestions appreciated.
If you want musical sounding speakers I would look for something else other than B&W. Something from DeVore Fidelity, Sonus Faber (at least Olympica line or higher), Harbeth, Roger, Spendor, ATC, ProAc, Accoustical Engineering, Vienna Acoustics, Wilson Audio, Wilson Benesch, Magico, Raidho, Vandersteen.

B&W 800 series D3 is great for home theater and is one of my favorite high end home theater speaker system but not for 2ch music. If it's for 2ch music your money isn't wisely spent on B&W.
There are countless other cheaper options than B&W that are better for music. 
@caphill - what is it about the B&W D3 that you don't like for music?
The B&W 800 series D3 aren’t bad for music but my point was that there are other speakers that cost less than the B&W that are more engaging with music and are more musical overall with richer timber and tonal color and possess more natural organic relaxed presentation and fuller sound than the B&W. When used for music to me B&W musical presentations sounded somewhat processed lacking natural organic sound especially with vocals and string acoustic instruments lacking midrange bloom and image depths and possess very forward presentation that I found them can be somewhat unpleasant at times for music especially with standard resolution digital recordings such as that of bad CD recordings. To me B&W fails to convey that lush emotional expressions of the artists and players.
I think I am not the only one who feels that way.

However, when it comes to details, clarity & resolutions B&W is top notch but that isn’t the only crucial elements that I’ll be looking for in order to achieve musical enjoyment from a system. Details, resolution, attacks, speed are important for movies (home theater), especially with those lossless HD surround sound formats eg DTS HD MA, Dolby True-HD, Dolby Atmos, DTS-X, which makes movie watching experience very exciting. That’s what B&W 800 series D3 are good at IMO.

I have to admit that the 800 D3 models are quite a bit better than their predecessors D2, D1, etc etc. I just couldn’t stand the previous B&W 800 series D2 models. The D3 are indeed better more realistic sounding than their previous D2/D1 models. B&W finally realized and moved away from using kevlar material for their midrange drivers.

But again it all comes down to personal preferences and tastes when it comes to speaker choices. You and others don’t have to agree with me.

B&W is perfect for home theater application IMO and is my to go choice for home theater.
I’m not bashing B&W as I am a B&W owner myself strictly used for my home theater room. I do own the latest B&W 800 D3 speakers for front with the matching HTML1 D3 center speaker and all custom theater in-wall B&W 800 series D3. I love them. They are spectacular.
Huh, that's interesting.  I am a B&W owner and had the D2 and now own all D3s.  I have the complete opposite experience from you, caphill.  My B&W D3 are extremely engaging for music and are very rich and full sounding.  It at all, I would say the midrange is slightly laid back when compared to other more forward speakers, such as Monitor Audio and such.  I think it may be a synergy with your amplifiers / cables.
Like I have already mentioned above that yes the D3 is more refined and have different sound profile than the D2 and indeed more musical than the D2 but they are still other speakers that cost less than the D3 but more engaging with music.

As far as synergy.....well, my B&W 800 D3 are in my dedicated home theater room strictly for home theater duties.
I drive them with the Classe Delta CAM-600 monoblock amps (class AB) and they sounded terrific together. I am using Transparent Reference speaker cables for them.

However, I have also tried driving them with my other amps that I have had in my separate dedicated reference 2ch room. So we literally dragged my B&W 800 D3 over to my dedicated 2ch listening room and had them hooked up with a pair of D’Agostino Momentum M400 monoblock amps before with the ARC Ref 10 linestage preamp + DCS Vivaldi full four stacks served as my digital front end as well as the Kronos Pro turntable + ARC Ref 10 phonostage pre served as my analog front end. I had some people help me with the move and placements and everything as the 800 D3 are big and quite heavy.
And when I compared them to my previous Wilson Audio Alexx that I had in there at the time, no comparison.
My speaker cables are Transparent Magnum Opys. Interconnects and power cables are Transparent Opus.

Recently I went through a significant upgrades with my stereo setup that I have in my dedicated refetence 2ch listening room. I traded in the ARC Ref 10 linestage pre and the D’Agostino Momentum M400 monoblock amps for the Naim Statement gears which consist of the Naim NAC S1 linestage preamp and the Naim NAP S1 monoblock amps. I also traded in my Wilson Alexx for the Magico M6. But I keep my DCS Vivaldi full four stacks as my digital front end components and I still have the same Kronos Pro turntable with the ARC Ref 10 phonostage pre.
Last week we had my B&W 800 D3 dragged over to my reference stereo listening room again and had them hooked up to my new Naim Statement gears and compared them to my Magico M6. No comparison. I know it isn’t a fair comparison as the Magico M6 cost $176k a pair and the 800 D3 cost only $30k a pair.
Hmmm, seeing as how the Wilson Audio Alexx comes in at $109,000 retail, I don’t think that’s a fair comparison either.

So, when comparing the cost of a B&W 803 D3 at $17,000 a pair. What speakers would be better AND cheaper?!?
Or even the 804 D3 coming in at $9,000.

Ultimately, I don’t think I can come close to the performance of the B&W speakers at that cost, especially with the diamond tweeter. Now, beauty is always in the eye of the beholder, and there are definitely other speakers that are engaging, but they all have different characteristics. I have seen the brand Joseph Audio mentioned as a very competative speaker. They use the Seas Magnesium woofers and the Seas softdome tweeters. The Magnesium woofers have extremely high resolution and really "sing". They are definitely very engaging, but they do have a resonance peak at 5khz that can affect things and could contribute towards a slightly "metal" sound. The softdome tweeters are excellent and also "sing", but they do put a slightly tube like signature on the highs that are not their with the B&W D3. B&W D3 are slightly more laid back in the midrange, but have significantly more clarity in the highs.

In the end, it all depends on what you want and what your preferences are.
IMO the Sonus Faber Olympica iii ($13,500/pair) and the Olympica ii ($10k/pair) are more musical or I should say more engaging with music than the B&W 803 D3 which retail for $17k/pair. My friend happens to be a dealer for both B&W & Sonus Faber and one time we had shootout between the SB Olympica iii and the B&W 803 D3 at his shop. Both speakers were paired with Classe Delta CAM-300 monoblock amps (class AB), Audio Research Reference 5 linestage preamp and a Naim ND 555 streamer/DAC + Naim 555 PS DR separate power supply unit.
So all the electronics are of high bars and we sat down for at least 2 hrs listening and comparing between the two speakers. We found that the SB Olympica iii is more engaging with music especially with piano and string instruments. But when we fed them with high resolution materials of great recordings we found the 803 D3 to be quite engaging and it’s got to the point where I can easily live with them with high resolution materials of good recordings.

@caphill - just following up.  I did get a chance at RMAF (first time) to hear a bunch of speakers.  The Sonus Faber are definitely an excellent sounding speaker (my friend has a set of bookshelves mated with all Krell Evolution generation electronics that are excellent as well).
On the B&W D3 note, I heard the 800 D3 in three different rooms.  The main B&W room had Simaudio Moon (if I remember right) and the sound was very clean and clear but did still have a little of that Class A smoothed over sound in the mids.  The second room was even more smoothed over.  In the third room, the 800 D3 sounded so bad that if that was my only exposure to B&W, I would totally walk out of that room and forget about B&W forever.  In actuality, I have to wonder how many speakers I heard that I would have thought sounded amazing, but were compromised somehow by an overly colored tube or too-smooth Class A amp, lol.  In reality, I love my B&W D3 at home here and was surprised that my system actually beats the crap out of a LOT of the RMAF rooms.  There were probably less than 10 rooms that actually sounded great to me.  Many sounded "nice", but just didn't reach that amazing level.
I did hear Wilson bookshelf speakers and I will admit they were pretty damn great sounding. It was tube gear, so it's difficult to know how they will respond on Class AB solid state. 
@topedwards - hopefully you listened to a lot at RMAF.  I would caution wit the Focal speakers.  I think they would be just fine with your McIntosh, but the Focal are fast and definitely have a thin/hollow midrange and midbass.  They would likely do very well with a Pass Labs full Class A, but your Mac will have a very laid back midrange and could be a great synergy.  I think you probably want a very high resolution to mate with your McIntosh.  Focal would be great.  Others that I have heard could be B&W D3 or Audio Physic.  The Sonus Faber definitely sounded good with McIntosh, but they are not the most detailed/forward speaker.
Oh, one more recommendation (and I did this in another thread) are the new Revel Performa Be speakers.

True. I have heard the B&W 802 D3 at the shop driven by all McIntosh tube power amp and preamp and didn’t like the sound at all. For some reason, B&W will not pair well with some tube amps, not all. Better off with SS amps. I think the B&W D3 do pair well with SS McIntosh amps, Classe Delta series class AB & Classe Omega series class A amps, some Sim, D’Agostino, Ayre & Naim amps among others.

My B&W 800 D3 front speakers that I have in my dedicated home theater room are driven by a pair of Classe Delta CAM-600 monoblock amps (class AB) and they sounded spectacular together. My matching B&W HTML1 D3 center speaker is being driven by a single Classe Delta CAM-300 monoblock amp (class AB), and the rest of my surround speakers (matching B&W 800 D3 series custom theater in-wall speakers) are driven by two Classe Delta CA-2300 stereo amps (class AB). And finally, my 4 overhead height ceiling speakers for Atmos setup are driven by two Classe Sigma Amp2 amps (class D) since my new Lyngdorf MP-50 AV processor does not have RCA single-ended analog audio outputs only XLR. For those 4 overhead height ceiling Atmos speakers I was originally gonna get the Clase Sigma Amp5 five-channel amp but the problem was that the Sigma Amp5 has XLR inputs only for first two channels and the rest of the channels are only available in single-ended inputs. Overall, they all sound terrific together for home theater use.

However, last year I did try bringing my B&W 800 D3 along with the Classe Delta CAM-600 monoblock amps over to my dedicated two-channel listening room and hook them up with the ARC Reference 10 linestage tube preamp that I had at the time with the DCS Vivaldi full four stacks (Vivaldi master clock, Vivaldi upsampler, Vivaldi DAC, Vivaldi CD/SACD transport) served as my digital front end source components. They sounded spectacular together and those were great combo for the B&W 800 D3 IMO driven by SS amps (Classe CAM-600 monoblocks class AB) paired with the ARC Ref 10 tube linestage preamp. Then I also swapped the Classe CAM-600 monoblock amps with the D’Agostino Momentum M400 monoblock amps that I had in there at the time and the overall results was also spectacular.

About 15 years ago, I drove B&W Notilus 801 with Jadis 500.

That combination gave most powerful bass and wide soundstage that I had at my home. 

I used CEC TL0 and DCS Elgar for front end.
B&W speaker sound fidelity beats any other speakers in every class for musicality, transparency, detail, sound stage - they sound as close to live music as you will get.

My 2 cents I'm driving my 802D3 with Tenor OTL and generally don't push them to 90db at the listening location, the sound is exquisite.  They seem to still have headroom if you can stand to be in the room above 90db, no stress on the amp or the speakers.  I've recently invested in an Accuphase DG 68 to overcome room acoustics and am interested to see if it really is worth the money, on Fleetwood Mac and Jars of Clay now I'm getting satisfying bass and low end otherwise on most recordings it's slim.  Ensuring the spikes are dug in and the nuts are locked make a difference tightening up and defining the bass.

@gebowers In my experience B&W speakers sound very "hi-fi", with boosts in upper mid to make it seem more impressive upon show room audition, however over long listening periods the presentation become unnatural and fatiguing.