From following this thread, it seems M3's would be a great choice for surrounds and ceilings. But, if I can get a pair of on wall M22's cheaper, are they a good choice for the side surrounds? Or is it better to be uniform with M3's all around?

Denon x4500h
ADA-1000 x3
VP160HP
M5HP x2
M3OW x2 sides
M2OW x2 rears
M3 In-Ceiling x4