Hate to disagree with Brent, but I am sure I have read somewhere that somebody is running the 661 with M80s with no troubles, it just depends on how loud you want it to go, I am quite sure that for most listening levels the 661 would work fine.

Anyway Congrats on the new purchase!!.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70