The TC2 finally got rid of my CEL that I've been dealing with for months. I pushed the car into the high 5k rpm range and still nothing (CEL wise). The chip makes the car pull a lot smoother in the whole range and gets really going after 4k although you can notice some difference in the 2.5k and later range. It might be that the chip helps more with the intake around 4k, but the difference is definitelly noticeable the 1st day. All I now need is the lightwight pulleys and lighter flywheel and I'm set to go... well along with new suspension, but that's another story.