As the distance from your home to Southern California increases, the ease of upgrading to Stillen's 3.90 gear presents more challenges. As an interim and maybe permanent alternative, I installed Michelin PS2 345/30/19's which are about 1.6" smaller in diameter than the stock 315/40/19's, which, in effect, makes a significant change in the gear ratio. My speedometer runs about 10% faster than actual speed, but as previously posted, it's an easy calibration correction to the SCT Tune. The results are very dramatic. The car has Heffner's pulley and a SCT dyno tune from Jerry Wroblewski, and the seat-of-the-pants feel is similar to driving Shelby#18's Whipple X1. :cheers