is there anyway that i can boost my performance for my 3.8l by adding a chip or anything else?

 

There is no "chip". You can use a program like hp tuners to retune your computer. However you will need a laptop, the software (around 400-500 bucks), and the know how. You can also send your computer off to a company called pcmforless, but i would only recommend that for cars with basic intake, exhuast mods.

 

I have a CAI and flowmaster muffler on my 97, AT,3800. If I were to get my computer retuned will the car run hotter? What kind of MPG difference should I expect? What kind of HP gain am I looking at

 

You can have your car "tuned" by a reputable shop with a dyno. Most places around here charge around 450. Having the car always get u the last horsepower available. Mail order tunes from pcmforless are pretty darn good for the money.