My receiver is Onkyo 797. According to the set-up manual, you should choose the impedence to match the lowest rating of your speakers. I believe the VP150 is rated at 6 ohm and that's what I chose to set-up my 797.
Unless you really like M80ti because you want to play them LOUD most of the time, you may be better off to go with M60ti. I don't know what model your Denon is (1802, 2802 or 3802?) but it is safer to avoid 4 ohm speakers although I have read that the 2802 and 3802 would have no problems pushing 4 ohm speakers.
Regards,
HT_Man
