what is the widest rim and tire i can put on my 02 gt and what offset do i need i like them to be about the hight as the stock 245/45 17

 

You can easily run a set of 17" or 18" wheels with the OEM tire diameter of 25.6", just the profile sidewall is lower on 18"s. Not a problem to run 9" +24mm off-set wheel with 265's up front and up to a 10.5" +28mm off-set wheel with 315's out back.

These off-sets have a slight bit of variable and not be a problem.

Jazzer