Dean, I'm also thinking that maybe your 2807 wasn't in top shape. At the 95dB level that you mention, although it's too high for continuous listening without hearing damage, the 2807 should easily power the M80s(something on the order of 10 watts)with inaudibly low distortion. I've also wondered about the difficulties which you've described in the past in setting up its Audyssey MultEq XT, which also isn't really typical.
The new Onkyo has nominally the same MultEq XT as the 2807 with whatever improvements have occurred in past three years and which could improve the in-room results independently from power output. You didn't mention it specifically, but if you had Dynamic EQ applied with Audyssey this would also make a significant difference compared to the 2807.
