The 667 will work just depends on how loud and how long you want to be able to play the M80's. Now I believe the 667 has amp preouts (yes?), so you could easily add an external amp to run the M80s if the 667 shuts down at all.

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