How big is your room? My first thought is that the 70 wpc (I think) will not be enough unless you have a pretty small room. Youm might look at the Rogue M150 mono blocks and the new Rogue Perseus pre.
I used to drive KEF Q1's (typical 8 ohm, 2 way monitor) with a mighty Almarro 3 watt/ch integrated (EL84 tubes).
I could play them louder than I needed with this amp.
I don't see why 80 watts/ch would be "underpowered" unless you're trying to reproduce Ted Nugent in your living room.
P. S. Try before you buy...
I am the Pathos agent is South Africa, and would only like to add that according to my knowledge Pathos use some of the B&W models in their development work. Not 100% sure the details, but in a response to a similar question from my side Pathos replied that Classic One sounds good on a pair of B&w 802.
I heard this speaker with MAC integrated which is 75w/ch. Sounded nice but was not able to play them at realistic levels. MAC would give up. Heard them in another store with MAC 100/ch solid state amp, it gave up playing Metallica at a relatively good level, but I would not call it too loud, or in that matter, it was not near reproducing James Hetfield in the room. Actually a right channel on that amp completely shut off. At another place I heard these speakers with C-J CT6 tube preamp and Premier-140 tube amp and it was really good, but we never went too loud. I liked it a lot with the C-J stuff. Smooth and strong at normal volume.
Personally, having owned the N803 for number of years, I had them set up at various times with McCormack DNA-0.5 Deluxe, then DNA-125 and now DNA-225, which is a really nice match. The more power the better for these speakers. B&Ws are power hungry. Keep that in mind. They will sure play with that Pathos amp, but I doubt 70w/ch would make the speakers or you happy. I would go for a tube pre and solid state amp. BAT tube pre and solid state amp would most likely be a very good match for these speakers. Or that C-J combo I mentioned above. Good luck.
Ok, after reading all of the posts. I like to thank you for all the comments. I went with the Mcintosh MC2000 Amp and C2200 Preamp. I know is a big jump from my original intention. I am currently saving for the B&W speakers either 802D or 803D. I probably lean more to the 802D but that mean little longer waiting time to save enough $$$ for that. While I waiting for my saving to grow. What is the recommend speaker wires for my system. Also what is the recommending surge protector or conditioner do I need. I am use to be an electrician myself so surge protector is a requirement for me. As for power conditioner is not that critical because I already have dedicated line to the system.
You'd want a surge protector that would not harm the sound, so I would suggest something passive, like Shunyata Hydra for example. I own 2 Hydra2 units. Very nice sound with reduced noise floor.
As far as the wires, after trying lots of interconnects and speaker cables, I found Acoustic Zen to be a very good match with the B&Ws. I use Acoustic Zen Satori Shotgun speaker cables. Awesome cables and very affordable. Interconnects I use are Acoustic Zen Siver Reference MkII from source to pre and Acoustic Zen Matrix Reference MkII from pre to amp. Just something to consider and put on your list of cablkes to try. IMO, should go with balanced interconnects if your components allow it(the amp and pre do, I beleive).
In any case, if you do go with B&Ws, make sure you get a proper speaker cable. B&Ws will not sound good with a single run speaker cables, you need a bi-wire sp cable set, prefferably a double run, such as the AZ Satori Shotgun. Check them out, they are specifically designed for a 3-way speaker, such as B&W 803D or 802D.
Best of luck. You'll have an awesome system with the McIntosh and B&Ws.