Winterpeg,
Interesting question. Off the top of my head, I'd say there wouldn't be significant advantage, because the Denon's power supply still has to come up with the current into the low impedance that it "sees." But I'll ask my colleagues on Monday. And if you really want tons of current, get a big, fat separate stereo power amp for the M80s, or a couple of monoblocs.
I've never recommended bi-amping for typical home installations (there are applications for professional monitoring at extremely high playback levels where it can make a difference) because I've never heard significant audible differences in a normal-sized room (2,500 cu ft) with either bi-amping or bi-wiring.
Regards,
