I may have discovered a bit of a concern when I calculated top speed for the car.
With the engine revving to 6000 RPM, a non overdrive transmission (1:1) final ratio and the stock 25 inch tall tires the top speed will be only 109 MPH.
With the engine revving to 6000 RPM, an overdrive transmission (0.87:1) final ratio and the stock 25 inch tall tires the top speed will be 125 MPH.
With the engine revving to 6000 RPM, a non overdrive transmission (1:1) final ratio and the stock 28 inch tall tires the top speed will be 121 MPH.
With the engine revving to 6000 RPM, an overdrive transmission (0.87:1) final ratio and the stock 28 inch tall tires the top speed will be 140 MPH.
UPDATE: I looked at more transmission overdrive ratios and it appears they are around 0.75. With that ratio we should be fine without changing tire diameter.