Seek, the 667 has preouts for an amp so no matter what you are good to go with M80s and VP180 and the 667. Once you have the speakers and have tried the 667 on it's own, if you find it to be lacking or going into protect mode at the volume levels you listen to, all you have to do is buy that separate amp and use the preouts from the 667 to feed the amp and your power issues will be solved, you can stop worrying about it.

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