It is interesting that the Denon guy would say stay with 8ohm speakers. Denon is one of the recommended brands Axiom mentions that are fine with m80's. My 5yr old Denon 2805 has never had problems with my previous m60's, or current m80's.

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