Hi guys. Just to let you know about this setup I just tried today. M60's connected to A and M2's connected to B, a EP175 sub and a yamaha rx-v2600. I must say those little M2's are absolutely amazing with the sub. I remember audio expert Jean-Claude telling me that all I needed was a pair of bookshelf and a sub. But, since bigger is always better, I went for the M60 and M2 as surround. After trying the M2's as mains I can be pretty sure you don't need florstanding speakers in a small/med size room. I did this comparison in a 19x21x8 with room treatment especially in the corners. Initially I had this system in a 12x15x8.
I hope this helps somebody out there. Btw, I should have listen to Jean Claude. He didn't try to sell me the M60's and he actually recommended the M22 as more tha enough and "youll be surprised. Even the M2 rocks...so - He was right!!!