In a typical 5.1 setup the surrounds should be to the side of the listening area or slightly behind.
My couch is up against the wall so I have my side surrounds mounted on the back wall, but they are spread out to the sides and pretty close to the couch. Is there something keeping you from placing the speakers on the side walls?
Anyway, I recently got a 5.1 setup consisting of m80's, vp150, qs8's, and ep500. My room is 2150 cf and it sounds great. The m80's will work fine in that room.
I think you will be very happy with axiom speakers. What are you upgrading from?
