Can't speak for the M80's, but my 2805 drives my system nicely. I have heard the Denon will handle 4ohms fine, just not sure if that applies to all models...

M60's VP150 EP350 4-Qs8's
Denon 2805


M80s VP180 4xM22ow 4xM3ic EP600 2xEP350
AnthemAVM60 Outlaw7700 EmoA500 Epson5040UB FluanceRT85