Early M80's ti (v1?) had the midrange drivers running without a HP filter. So the transition between ti to V2 had significant changes made to the crossover which would impact sound quality. Drivers are tweaked according to Axiom as well over the years. V3 also has cosmetic changes such as the colour of the dustcap and magnetic grilles.

I’m armed and I’m drinking. You don’t want to listen to advice from me, amigo.

-Max Payne