Apparently all 6.5", 5.25" and tweeter baskets were changed to cast for v3. The mid-woofer is a wee beastie. It looks like it's capable of a good half inch peak-to-peak excursion which is partially responsible for the stunning performance of the M2.

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