I would swap in a set of M2's and see if the sound stage is different, I would expect a huge difference in sound from the M3's to M2's as centers. I know Huztal is going to mount a some M3's one above and one below his screen and has them side by temporarily and he loves the sound. I am sure he will be along shortly to offer more.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70