Thanks! People have certainly been willing to provide helpful input on this forum.
If you decide to go with direct radiating back surrounds you shouldn't hesitate to use the M2s.
I have come to the realization that the M2 would be fine for a direct radiator.
Now, if I could only make a decision on the direction to go. I measured, and the rears will be about the same distance from primary seating as the main L/R are. I watch 90% movies in this theater for now (surround music hasn't taken off). Would I be happier with reverberant speakers or not?
The "audition both" option would certainly be helpful....
