>>You have enough room length that the M80s can be out from the back wall a bit, which really seems to help.

Agreed. As long as the room isn't too big, M2s plus a nice sub make a really nice HT system.
M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8