Another fellow axiom owner.
Generally, because the M80's are 4 ohm, people say to stick with H/K, Denon Nad. rotel, outlaw or other companies that are known to handle the 4 ohm load well. At least that is what "they" say. Pioneer and Yamaha, Kenwood and a fewmore are frowned upon on the axiom website for m80's. That being said, I wanted to try a yamaha 4600 and see for myself.