Luc, I would suggest getting ahold of one of the M80 owners that migh be near you so you can compare the sound of the M22 and the M80's.
I went from M22s to M60 (briefly) to M80s and I, like you, had felt there was possibly something missing with M22/sub, IMO there is. I feel that the M80s full spectrum ability adds to the overall feel of the sound, the bigger question is, can you justify the extra money for a warmer/richer feel.
Here is a
link to an older thread of my experience with M22/M60/M80 comparison.
