I would not concern myself overly with matching the surrounds identically to the front.

As for the model, I have not heard either so take my assumptions lightly but from all I have read here, I would add the clarity of the M22s to the solid bass of the sub and enjoy the near sonic perfection. If you had a none or a weak sub, then the M3s might be considered for their slight bump in the midrange that is said to make them sound a bit deeper.

With great power comes Awesome irresponsibility.