I am ready to order 2 back surrounds. I know this has been hashed around somewhere in the not too distant past but, do I go for m2 or QS8 for the 2 backs? (I can't consider anything larger due to room constraints,furniture etc) I go roughly 50/50 music/movies. I have the 60's, the 150, 2 Qs8 sides. Room is 27 x 14.5 x 8. I have 2 very small, old Polk monitors there in the back now. They don't seem to add that much Thanks for all input.