The importance of a good tune
 

did you know that if you just bolt a cold air intake to your corvette without tuning it, the car will actually loose performance, not gain it. when you change the diameter and shape of the intake, it changes the way the air flows across the mass air flow sensor, and it needs to be recalibrated so it reports the right amount of incoming air to the vcm. and it is the same situation with the exhaust. and don't fool yourselves thinking the vcm will adjust and trim itself. the vcm is only self adjusting when it is in closed loop. and it can only operate in closed loop when the airflow across the maf is stable. the second you stab the gas pedal, the first thing that happens, before the motor climbs in speed, the vcm switches to open loop and relies on its base programming. and open exhaust and intake without a proper tune will make an ls or any other motor go dangerously lean at wot.