Bruno - I can't speak for the M80's but I do own their M3ti's with a sub. I have auditioned Klipsch RF 52 and will confirm their midrange is not as well defined as my Axioms. Although the horn tweeter does allow for a wider dispersion, in no way is it as prestine and smooth as Axiom's (all of Axiom speakers share the same tweeter technology). In my opinion, it's going to be the midrange where Axiom will beat the Klipsch hands down. My M3's are bookshelves of course, but the Axiom sound is something I'm going to live with for a long time. Regarding the AVR question, you won't go wrong the Denon, HK, NAD or Outlaw.
