I guess you could do a few things. Gut the wiper motor, remove the heater core (especially if it's an A/C car) My car only looks like it has a heater box.... You can also gut the blower motor, remove the dash pad, door/kick/rear panels and drill holes, remove all the window mechanisms, replace the steel bumper brackets w/ aluminum, remove any undercoating, those are a few things I can think of off the top of my head. I guess depending on car you could go w/ fiberglass parts. This car has a glass lower valance.