Originally Posted by Neothin
Why would you have to change the computer around to account for a different rear-end gear than stock?
Well, in truth you don't have to. BUT if you like your speedometer/odometer to be correct, and the transmission to shift at the proper RPMs, then you really would want to correct the gear ratio in the computer. Depending how the car is set up, it could also affect ABS and traction control.