Welcome to the Axiom Family. I have a question as to how much room you have from the rear channels to the listening area? If there is little to no room then you may very well find another set of QS8s to work very nicely, if there is some breathing room for them, then your current direct radiators or a set of M2s might work better. Just something to think about, everyone has a different idea as to which they prefer for rear channel speakers. You may need to play around with the QS8s as rear channels just to see which you prefer.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70