I think you will have a kicking little set up and considering the age of the Advents, the M3's should hold their own, and then some. I own a pair and they can rock. If you like movies, you may want a little more sub than the 125 but I don't own one so who knows. I would think a 175 but probably a 350 would be best. Don't know your budget though.

M80's(2), VP150, QS8's(2), M3's(4)