Denon is actually one of the lines that are recommended for 80's, as is HK. My manual on the 2805 says not to go below 4 ohm, it does not say 4 ohm won't work.

You'll be fine, Axiom recommends Denon for 80's as well.

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