On mine because it is a track only car, I've taken out the door windows and mechs, when upgrading the cage I got rid of most of the sound deadening material, running lexan side windows etc. but could still run lexan rear window.

I have this silly idea that getting the car (with the overbuilt cage that must weight 170lbs) down to some crazy number like 1475 without driver.............currently I'm at around 1650.
Nothing money won't cure......................make the whole chassis out of carbon fiber and use an alloy block and it might get down to 1300lbs..............anyone want a $250,000 Datsun 1200!!!!!

Tom

PS I still haven't got into the aero mods..................flush windshield, smooth drip rails.