Hello Jim,
Bridgman is essentially correct, however, the M80 crossover changes took place several years before the V2 designation was applied.
The series of double-blind listening tests between the "old" M80 crossover and the new tweaked version all happened during the summer of 2003, and the new crossover was implemented by Fall of 2003 as a running change. That resulted in audibly smoother upper midrange performance, so all subsequent M80s incorporated the new crossover. The V2 designation wasn't applied until 2005.
There have been no significant changes to the M80 crossover since 2003. By "significant," I mean that the changes would result in audible differences in tonal balance.
Regards,
