Yeah, my question was answered by you in your last post. Basically stating why you would want to change feathering shafts. When you do that, you will have to change much more than just the shaft including but not limited to bearings, shims, grips, head and so on.
As for what is different, every heli is going to be different. The V2 is different from the Pro, and the sport is different than the v2. That is some of the headache when you buy a knockoff heli, you have to figure out what one they are copying.