The M3/M50 have a simialr sound(I haven't heard the 50's going by other's with this one), The midrange on them is slightly recessed compared to the M2/M22.M60/M80 thus giving you a timber mismatch between them. The more neutral to prominent midrange of the latter speakers gives them a more forward sound to many ears.

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