I got Denon AVR-3806 driving my M60. It's awesome. I think it should work fine with M80 as well. Of course if you have the $$, you might want to get the 4806 or their top of the line 5805 instead

But back to reality, I would say 3806 combined with Outlaw external amps would be great for M80. I only have the 3806 with no additional amps and it's good enough for my M60 in 16'x13' room, but you might want to consider getting the extra juice for M80 though.