FallenAngelHIM said:
then you can replace your windows with some kind of plastic.
As stated above, switching to acrylic in place of glass for your windows will save alot of weight. Keep in mind however that you probably don't want to switch out your windshield and rear window since acrylic scratches easily, and those two pieces of glass in particular are weight bearing support structures should your vehicle ever end up on its roof.
Wildman said:
get some lightweight 15's, those will make a bigger difference than removing 100lbs I would imagine.
I forget the actual number, and can't seem to find it online at the moment, but each pound of weight you take off the spinning masses (wheels + tires) is the equivalent of like 3 or 4 pounds of non-spinning mass. (Anyone know the exact amount?)
I'm assuming that since you said you put in racing seat
S, that you don't intend to make it a full race vehicle. In that case, the only things I can think of that you could readily do to the vehicle with out sacrificing drivability would be a light weight wheel/tire combination and removing the plastic tray under the engine (not sure if 6th gens have them, but my 240SX had one).
If you wanted to go all the way with the weight reduction, you could also remove the headliner, sound deadening/insulation material and door panels, front passenger seat, rear seat, rear brakes, windshield wipers, center console, carpeting, sound system and lights (head, tail, brake, turn and reverse). Replace the fenders with carbon fiber fenders (
clicky). Cut the exhaust so it exits at the front of the vehicle (no cat + no muffler + less piping = less weight). Replace the stock steering wheel with a quick release or other such racing wheel (obviously though this messes with the SRS system). Replace the gas tank with a fuel cell. Swap the battery out for a lightweight battery (
clicky ). And not sure how this one works, but I know I've seen it before on some racecars, you can remove the starter and just hook it up to start the motor. Can't really think of anything else right now.