Best speaker in the $5-10K range. Details below.

Yes he would.
I've underpowered Maggies in the past (and it's not good).
Better to choose another speaker unless he gets more power.

On the other hand with his budget he could afford to do that if he could get the Maggies for a good price.

Get the Maggies used for a good price and buy a massive SS amp (high quality and clean like the RS). Maybe enough left over for a bottle of wine and a cigar.

I differ from most of the posts here. I spent 10 years trying to get a pair of speakers to sound as good as they did at the dealer where I auditioned them, and never succeeded. IMO, there is no substitute for auditioning speakers in your home, with your gear, and with your music. It also helps not have someone sitting near you waiting for your opinion.

Because of that, and because of some threads here on Audiogon, I went for a home audition of Ohm Walsh 2000s. Ohm gives you a full three MONTH audition. In my case, while I paid for shipping to my home, I live close enough to Ohm's factory so that I could have brought them back in my car to save return shipping. So, if I hadn't kept them, I would only be out the original $50 shipping. I consider that a small price to pay in order to find out if I can live long term with a speaker.

You can find my review of these speakers here in the user reviews section. I love these speakers, and expect to own them for a very long time. Your budget and room size make the top of the line Walsh 5000 or the maybe the 4000 the appropriate choice. Having spoken with designer and owner John Strohbeen, I cannot stress enough how helpful he is. You can call him directly and discuss what you are looking to do.

For someone who cannot travel to audition speakers at dealerships, I think the in-home trial route (with a no-restocking fee policy) is the best way to go.

If you like the sound of your 6311's why not jump up the Usher line? There is definite improvement to be had. Those Bellas will push most Usher models, I have been using a VAC Phi 110(110wpc) on my Be-20's for quite some time now, it works wonderfully. You can pick up used Ushers for great prices. Just a thought....

Goldenear! Can't go wrong. They're dreamy.