I have no idea about M80v3 but the M100v4 is miles better than M80v2 in every imaginable aspect except the larger size and weight. The M2v4, M3v4, M5v4 and M50v4 are also better than M80v2 in delivering emotional satisfaction.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated