Ok so I've decided to upgrade to the EP500. Now I'm eyeing a pair of M80's. Currently my mains are the M22's. So I'm looking for some advice on this. If I got the M80's I could use the the M22's for the rear surrounds thus making a 7.1 system. But how would M22's sound for the rear surrounds versus another pair of QS8's? If it not going to sound good I'll just sell the M22's or use them in another room and possible order another pair of QS8's down the line. Just looking for some advice.

Here is a beautiful MS Paint image I created of the room. Forgot to put the VP150 in. But it's there.