When I auditioned the v3 Axiom speakers vs. my older Ti version (Ti were the versions before v2) I did notice an improvement - primarily in the tweeter. The new v3 tweeter has wider and more even dispersion, which also gives the v3 versions better imaging. The midrange and mid-bass sounded more or less the same, but the new v3 drivers can handle more power (and therefore, louder output) before they distort to the same levels as the older drivers.
It is by no means a "night and day" difference. It is still the much the same, solid, flat-in-an-anechoic-chamber sound that Axiom has strived for all along. But it is, never-the-less, a noticeable difference if you are comparing them head-to-head and actively listening for differences.
I'm no fan of Axiom's center speakers. At least, I wasn't until the VP180 came along. The VP180 is very, very good. But it is also huge (compared to most center speakers) and it isn't cheap (although it doesn't cost nearly as much as comparably large, powerful and bass-capable center speakers from other brands). The VP150, to me, just doesn't sound right. IMO, it's well worth the extra money plus doing whatever you have to do to fit the VP180 into your system.
The M60v2 is a very nice tower. If you were to have a v3 right next to it, I think you'd be able to pick out the improvements in the v3. But, like I said, it's certainly not "night and day" and I don't think there would be any problem at all with using M60v2 towers with a v3 center. But man-oh-man, spring for that VP180 if you can. It might seem insanely large and it might cost more than you were planning to budget, but I promise you, it's SO worth it - and even more so when compared to the VP150 or VP100, which really just don't perform up to the level of Axioms towers and bookshelf speakers for some reason.
