You're Denon would do fine with the M80s.My only concern would be if you were to put the 80s on the long wall you might not have enough room from the listening position to the speakers.If you were to have them on the short wall then you could go with the M80s.The 80s are not all that hard to place IF ya have the room to do so.There has been a couple people that could not get the placement right for what ever reason but it seemed they didn't have the room to place them right.....ie to small of a room.I have mine in a room that is 15x20x7.5 an I have not had any problems.If your iffy about having enough room to fit the M80s then opt for the M60s as Im sure they too sound fantastic.
