From the V3 I think the pretty much everything.
MidBase/Woofer
The new drive-unit is a 7" cone with an elliptically profiled surround of Santoprene artificial rubber, designed to achieve lower distortion, and deeper, louder bass.
The Cabinet is supposed to be improved as well. I used to have the Studio 60V3, those were my first entry into home audio, and I was very happy with them.
Studio is pretty much dead as it was replaced with the Prestige, which in fact do sound quite good, definitely a step up in detail, but there are so many options in that price range