TonyM, the M60 has dual 6.5" woofers in addition to a 5.25" midrange. The M2 uses the 5.25" driver, not the 6.5".

Also, I remember reading on the AVS board sometime ago that there are some problems with running dual centers (other than the increased load it presents to your receiver). Unfortunately, I don't remember what the specific issues were.

I'm sorry that I don't know more about it... perhaps one of our more knowledgeable board members may comment.