I have run a few posts on the subject. I'm building a track only car, from a 2002 C5 Z06. It weighs 3,100 OEM and the track car will weight about 2,550 when done.
Unless your building a track (RR) car, trying to lighten your car up is a waste of time. It won't change the performance and is expensive. The ways to get significant weight out of a car aren't going to be attractive for a streetable car:
Remove all interior ****pit materials down to bare metal, remove headlights, air bags, heater core, A/C system, replace front/rear windshield with lexan, remove side windows, new racing rims, carbon fiber body parts......
Sound like something you want to get involved with? That's what required to get a car down to racing weight.
Suggest you spend $$ on fun street mods instead. Good luck.