As to the sub upgrade keep the 350s as you plan on M22. If you were keeping the M80s the 350 may not be enough.
For me I went from the M22 to M80s found the spot I had the M22s set for my room the best place for the M80s, for positioning. Easier to find best placement with the size of the smaller speaker. When I changed to the M80s my SVS PB1000 was totally muted by the range of the 80s.
When I ran it with the M22s it was a wow performer.
Try to fix the gains and reverbs of your room and the 2 EP350s should be totally sufficient. With that complete WOW factor of good clean bass.
