Take a look at a bunch of other cars, that you race with,,I started out at over 3500 lbs with my car, and after shaving weight here and there, I`m down to 2700 lbs. and I still drive it on the street as well as race at the track. for every 100 lbs you loose, you should gain a 10th of a second, and make it easier on parts, you can also look at your brakes and wheels, for easier and lighter rotating mass, once you start looking around at what you dont need anymore in the car it just gets easier and easier to loose weight, you said you dont drive it on the street anymore, so lots can go, and you wont even need the glass doors, which "are" a real pain in the a$$.at least for now,,work on front aluminum brakes lighter wheels, back window- lexan, power windows and crash bars, sway bars, heater, wipers, and lots more,if you are all stock equipped, should be easy to gain at least a second off your time, and not even touch the engine.