I don't think that rubber tires are good idea for 1/12 and I really wonder why this keeps coming up. I know that F1 are a growing class, but I can't see this for GT-R. At least not on the West Coast or at the IIC. I personally see a problem with the tire size, a typical tire diameter of 1/12 is 41/42 and smaller.
Let's use 41mm rear as base line. The rubber tyre needs at least 4mm hight from the wheel. This gets us a wheel with a maximum diameter of 32mm.

Foam Tires work great and therefore we don't have to change it.