For Yamaha the Presence speakers are located above the front speakers and spread out further. This way the front sound stage is wider and it adds ambience. For my yammy if I used the Presence speakers I could not run 7.1 for rears, something to keep in mind.
I tried M3's as presence speakers as I had them around, however I did not have them in the ideal location. It was neat but I did not like the way the M3's were with the M60 and the M3's are too big for my set up. I would like to try it again sometime in a different room and with M2's though.
If you have the speakers and the extra wire give it a shot.
