Lee, it appears that you've been doing some reading in the realm of audio fantasy. Your "show the M80s at its finest" phrase implies that there would be some difficulty in achieving this and that a "high end"(i.e, high priced)receiver would be needed to do the trick. On the contrary, one of the wonders of the current audio scene is the availability of plentiful clean power at modest cost. Properly controlled blind listening tests indicate that amplifiers with flat frequency response from 20Hz-20KHz and with inaudibly low noise and distortion at their designed power output level(again, readily available at moderate cost)allow any speaker to perform at their "finest" within those power levels(certainly at the levels you mention for great classical music). Nothing more is possible from amplification.
For a unit with more up-to-date features, including Audyssey room equalization with Dynamic EQ and Volume, consider the similarly priced Denon and Onkyo models available as factory refurbs or the new models(e.g., Denon 4307, Onkyo 3007)if you're willing to spend a bit more than the $800 figure you mentioned.
