I also have a 2000 Gran Prix GT as a daily driver on a limited budget. Keep it simple and do just a few mods that will give you the most bang for your buck. I always like to do one mod at a time to see what performance gains each one make. Also because if the car doesn't run right you will know where to look for the problem. I recommend the Cold Air Intake first, then a couple of performance mufflers, then the reprogrammed
PCM. The
PCM has been my favorite mod because it really wakes the car up by changing the shift points and gives the car much firmer shifts. Those three mods should give your engine a 25 to 30 horsepower increase approximately which will make the car more fun to drive. Other than that you should put on a 180 degree thermostat to make the engine run cooler. Then lastly you will gain a few HP by removing the U-Bend in the exhaust and put on a Hi-Flow CAT. Other than that the HP gains are very small unless you're really ready to spend, spend, spend. It seems that
INTENSE has the best customer service to work with you and they have an excellent
PCM. After installing the
PCM don't forget to go to a GM dealer for the CASE LEARN (very important). You can read all about it on this website. Anyway I did all of these same mods on my non-supercharged GT and had no problems. The car runs strong an I have been very pleased.