Willy,
I wouldn't worry about it. I had the same dilemma when I was making my purchase. I Didn't know whether to get the M2's or M3's. I went with the M2's for the simple fact that I knew My HSU VTF2 sub would do an excellent job filling in the lower end. I didn't see the need for the lower frequencies of the M3's. You really can't go wrong with either speaker.