I will say one thing, these cars really benifit from weight reduction. Way more than more powerful cars i've owned. I had a water leak in my car. Well, i ended up stripping my entire interior to find it. I also took my system out. Huge difference, felt like a whole different car. Most of my savings were from the system and about 40lbs of water, so not really a savings but huge difference.
Anyway, i think the most benifit will be your wheels. Infact, i'd probably by get some 15 in wheels with some slicks. Just a pair, swap them at the track. Or get dot approved ones if the track is close to you (they really still arn't street tires, terrible wear).
Outside of that, the obvious carbon fiber stuff. Then it depends on how far you want to go, what you want to sacrifice.
But then there are the things your car has but you may not care about. If you don't use your sunroof but want to keep it intact, loose the motor. Or you like a stereo, loose the rear speakers. Don't care for an automatic trunk poper, loose that. And go down list. You can still loose a decent amount of weight and not loose anything you you'd really wish you had.