I think the M80s are really out of the equation because of the price and the fact that I won't be pushing the system very much.

My receiver is an Onkyo 705 - not the beefiest amp in the business to be sure but it fit my budget.

How would I connect two M22s to the center channel outputs? Would this be greatly better than the CP150?

I don't plan on listening loud - we really just want clear 'immersive' sound and some nice deep base accents to movies.