Denon's full range of avr's work very well with M80s, I have run my M80s with an older 1804 and my newish 3808 with no problems at all. Most seperate amps work with 4 ohms, ie. Rotel, Denon, Outlaw audio, Anthem etc., but there are always few exceptions, Emotiva is hit and miss.

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