My left rear went flat from the inside edge being bald. The camber on the rear wheels must make them wear out so much faster. My fronts still have a ton of tread left, so Im going to just get new rears. I have the conti sport contacts, but I noticed that the tirerack has 2 versions now, conti sport contact, and sport contact 2 Vmax. The vmax's are 200 more a piece....what's the difference?

 

I would use same ones that are on the fronts or get four new tires.

 

I believe the #2's have a much higher top speed rating. They were used on the 9ff 240mph car. They are the only tires with that rating.

 

They are probably made with different compounds to your original Contis so you're better off sticking to that.

 

I had an inside rear tire wear problem. Changing tires will not solve the problem. I had the car realigned and that took care of the problem. My problem was pretty serious as the tires looked good except the very inside edge, so it was hard to notice. If you change without realigning expect the problem to return.
I am not a tire expert but I would think mixing tires, even of the same manufactuer, would not be the way to go.