Sonus Faber Amati Tradition - How Many Watts Optimal?

Hi all,
I own a pair of SF Guarneri Evolution driven by a pair of Mcintosh MC75 MKIII and C22 and realized my room is too big for bookshelf. Just like many younger generation (I am 39) I like strong tight controlled bass while at the same time just like many audiophile I am always lusting for midrange to die for, so I have been lusting for Amati and last week during an audition in my local dealer I saw a brand new in box pair of Amati Tradition for a price I couldn’t refuse and I put a deposit. Now I am wondering about what amps I should drive my Amati Tradition with? I suspected it’s not an easy speaker to drive with 4 ohm impedance, sensitivity is quite high at 90db though, spec recommended 100-500 watts.

I like Mcintosh amps very much but I am not fanatical, initially I was thinking about driving the Amati in biamp while still utilizing my MC75 plus a pair more channel from new amps to save some dough but opinion seems to be divided in the middle regarding bi amping and it’s a big gamble for me to go bi amp considering the cost of extra cables.

What amp should I consider? I live in Indonesia so I don’t have much choice in regards of brands. I can easily source Mcintosh, Audio Research, Gryphon, Audio Note, Cary and some other more typical household brands. More exotic brands such as D’agostinos, Pass, T+A, Ayre and the likes are hard to come by and audition.

Lately I also been flirting with the idea of going integrated to keep cost down while keeping my previous system as second system and build an entirely new system around the Amatis, but I am still open to any suggestions because I know I will have difficult time explaining to my wife why I need two systems. LOL

Thanks in advance!
Interesting...I had SF Amati Tradition Homage Speakers.  I drove them in a very large room with a Raven Reflection MK2 Integrated tube amp and the sound was incredible and easy to drive.  I used KT 150 Power tubes and probably driving them at 62 wpc.  I am a Raven fan and they have great tubes and customer service.  Please take a look at their lineup online.  

What is your budget?  

Mac is generally good with SF as they are in the same family to a degree.  I am just not a fan of Mac.  

There are a lot of great integrated amps. Luxman, Aries Cerat, Gryphon T&A.  I liked the convenience of an integrated and I really don't think I sacrificed any sound quality.  
The Mc75s should work fine unless you want to shake your foundation. At reasonable listening levels you should have plenty of power. 
I looked at the specifications of your Raven Reflection MKII and it’s produces around 60 watts +/-. How does it handle your Amatis? Do you ever feel the lack of power when playing speedy and slamming notes? I don’t listen loud at all, on my existing setup I never went beyond 45% on volume dial on the C22. My budget is anywhere around USD 15-20K but I actually really like the sound signature of my MC75 and have no complaint nor desire to try other amps if I weren’t so concerned that my Amati would sound somewhat ‘weak’ lacking authority being driven by MC75. 
Do you think so? If that’s the case then I will be a very happy camper. Like I said above I actually have no complaint about the sound quality of MC75, just afraid that it will lack authority when driving the Amati. Initially I was thinking about bi amping MC75 to drive the Amati in vertical configuration but so many people in various forums doubts the benefit of bi amping so I consider bi amping as a very risky proposition due to the cost of expensive extra cables. 
You should be fine with MC75. Keep in mind both SF and MAC tubes have a very warm signature, which is fine if you enjoy this.

 Alternatively you can get two MC275 and bridge them as monos. Doubling power will add another 3db to your peak volume. Of course MC901 would be the best of both worlds, SS for low end and tubes for midrange and tweeter. 
Luxman L-590AXII is a Class A integrated that will make your SF less romantic and more detailed and accurate. It's one of the best integrated amps on the market now. 

But I recommend you stick with tubes all around. You can't beat the tube sound once you're used to it. Look into audio research, 160S, will be more detailed and accurate than MAC and still keep beautiful tube sound with plenty of power. 

You should definitely experiment. Also try a moderately powered SET if you can afford it. SETs sound beguiling with SF. 
I just came out from 17 plus years audio hiatus. Back then, I couldn’t stand the sound of SS amp but I realized that today’s SS are light years beyond the ‘old’ days SS. I even considered a pair of MC611 too. Having said that, if MC75 could handle Amati Tradition I will be very happy as the reason for my ‘upgrade’ wasn’t sound quality, it was just that I realized my Guarneri Evolution are too small for my big-ish room. 
I know this might be a stretch. What about the Rouge DragoN. This is a SS amp with 300 WPC at $4000 USD. It uses new tech and even though it is SS it has a warm tube like signature. It is designed by a tube based audio company. I know your budget is higher but this might work. 
Thanks for the suggestion, unfortunately there are not so many brands available in my country right now. 17 or so years ago I could find almost every well known brand here but not anymore. Most dealers are sticking to the more common household brands from big corporations such as Mcintosh, ARC, PSA, Gryphon, Audio Note, etc. Rouge was actually on my mind before I bought my latest gear but I just couldn’t find the dealer anymore. 
I don't have the Amati Tradition but I had both the Olympica III and the Amati Futura. I used Symphonic Line solid state 100 watts pure class A, Audio Research Class D stereo and monos, ARC Ref75 and ultimately REF250 SE monos.  I thought they sounded wonderful and musical on soldi state but I am still a tube fan. I loved the REF75, was really magical.  I went up to REF250SE monos, because it was one more layer of detail and more open. Dynamics were awesome on a wider range of music and I am building a large sound room and was planning ahead a little. Hope this helps. 
So with the Amati Tradition Homage speakers that I had with the Raven Reflection, I never had to turn the volume past say 1/4 plus.  Or in clock terms maybe 10 o'clock.  Very rarely I would play at 50% volume which basically the neighbors could hear it.   
That’s very assuring to know that your small Raven is enough and that information was exactly what I am looking for. I have decided to try the Amati with my existing setup first, it’s rated at 75 watts with many tests showing 100 watts actual output. 
I have the homage SF amari, and I run then with 2 mc 501s and they sound crisp and powerful.