>>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, SVS PC-Plus 20-39, EP500
M5HP, Sierra-1, M40ti
M2ti, M3v4, VP100