NA not SC XFire, you see me shift from 1st to 2nd at the 7 sec mark. For exhaust, I had a straight pipe fabricated and usually just install it the day before a race and put the stock system on the next day. I did enjoy keeping the straight pipe on all summer this year and I really enjoyed it. Not too loud below 2K rpms, but has a nice growl through the mid range, and then tapers off above 4.5K.

WRT tires, 245-35-18 is about the max for up front. I ran 245-40-18's for 1 season and rubbed the inner fender well. I'm going to try 255-35-18's next year, but have the 245's waiting in the wings in case I have contact. Also, I got some MB SL550 wheels (18X9.5) for the rear end for next season. Hoping for more contact patch and torque.