Adding a second sub made a big difference for me as far as smoothing out the bass. I didn't need the first sub turned up as loud to compensate for bass loss in certain areas of my room. Also upgrading to the EP400 didn't hurt either.

M22v2
vp100v2
M2v2 surrounds
EP400/EP125
Onkyo TX-SR876
Oppo BDP-83
NAD C542
Sony XBR9