Jake and Ken,
I may have stated that incorrectly, I was only referring to the posters situation. If I understand him correctly he has m2's, which should be left/right surrounds on the back wall, in addition, he wants to put a Qs8 in the middle of those two speakers on the BACK wall. I was just trying to say he would be better off using the Q's for the left/right position. Putting all of these speakers on the back wall is not a good idea, that is all I was trying to say. Heck, I have 4 Qs8's, two on the sides(as you should) and two behind (for rears).
M80s-VP180-QS8s-EP600-2xEP350 Denon3808 Outlaw7700
(M22-OWM22-VP100)-all in storage