Back in my days of "car modding", if it didn't serve a purpose directly related to the safety or performance of the car, it was discarded as being excess weight.
My last 65 Mustang had no back seat, carpet, headliner, or stereo, and all of the removable body panels were made from fiberglass (including the rear bumper).
On street tires and using pump gas, it turned 13's in the 1/4 mile at OCIR, and wasn't even built to be a drag racer.
