WhatFurrer cranked the M60's up a bit - still nice and clean and was barely able to hear anything he was saying at the same time.
That little bit of extra openness you heard from the 60's at that higher volume is what the 80's sound like all the time. They really are worth the extra money.
I think your receiver should be able to drive the M80s, The ES series is way more robust than the STR line up. I have tried my 12 yr old STR-D915(prologic reciever) with my M80s and worked ok till I went beyond anything I would call normal loud levels. Not quite the same ooomph as my Denons but it did OK.
