Welcome, Shawzy.

It's highly recommended that you use 12-14 gauge wiring vs 20 gauge as others have already mentioned. You'd want to be looking at the EP350, competitors equivalent, or greater to compliment your M80s, I think you'd find anything smaller a bit redundant where M80s are concerned.

Don't worry about your Denon 2809...never had a problem with mine running an M80 based HT.
Half of communication is listening. You can't listen with your mouth.