I know exactly what you are looking for when you're asking for amp specs that you can use to make a decision. It definitely makes sense, but it's not going to happen. I'll give you a couple of examples of why that is. One of the more popular specs when it comes to power amps is thd. The designer for brand A may say that for 100 watts into 8 ohms, 2% thd is acceptable amount of distortion. If you give the same exact amp to Company B to rate its power, they may say that 2% is too much distortion for a 100 watt amp into 8 ohms. Maybe they feel anything above 1% is not acceptable. So if that's the case, company B may rate the amp at 75 watts instead. Or they could go the other way and say 3% is OK and give the amp a higher power rating like 125 watts. That's what I'm talking about when I say there's no standard. It explains why you can go into Best Buy and get a 100 watt/channel for $200, and then find a high end company that's selling a 100 watt/channel amp for thousands of dollars.
Another example is what makes up a watt. Watts are volts x amps. 10 amps and 10 volts is 100 watts. 50 volts and 2 amps is 100 watts. 20 volts and 5 amps is 100 watts. You get the picture.
Of course, there's more examples than what I list here. So if you're now thinking, what are you going to do as far as picking an amp? You need a way to go beyond the limitations you now find yourself in with regards to specs. The way you do that is by listening to whatever amps you are considering. Audio a very hands on. You need to listen to as many different components as you can. As you gain experience over time, it gets easier.
Looking at your system, the B&W's are not big floor standing speakers, and your room is not that big either. You really won't have any trouble finding an amp that will work for you. I would be more concerned with sound quality than watts. Also, you mentioned above that B&W recommends a high current amp, and they don't do a good job of defining exactly what that is. Its expected that you'll be working with a dealer that can help you make a selection. Speaker companies usually recommend a high current/powerful amp because they want their speakers to sound good. If you go in under powered, sound quality will suffer. And if that happens, there's always the chance you'll blame the poor sound quality on the speakers, and not the amp.
