Got a pair of Pegasus sleeves with Michelin Pilot type tires today (Thanx Matt!!), and went to work. I narrowed the Tamiya wheel, then chucked it into a drill and milled the wheel down with a file. Still have a little fine tuning of the Tamiya wheel's edge to do, but the larger wheel and tire fits the car quite well.
Update: Finished up the wheel mods on the GT. Touched up all the nicks and scratches with Tamiya TS-30 silver, did a final bit of finishing on the wheel edges and glued them in the sleeves with Zap CA. The O.D. of the new wheels and tires are identical to the kit's wheels and tires, so there was no need to raise or lower the suspension to get the stance. Now it's off to the strip tank for the body and chrome parts...
Brian