Found out that the sound proofing material doesn't weigh much as all (1-2 pounds?) so I'll be reusing it. As for the carpet, it weighs about 40 pounds so I am installing some super lightweight fleece fabric that looks like carpet. Rear seats, seatbelts, tire and seat belt brackets are staying out.

Should lighten things up a bit.

 

Is the fleece premade to fit our cars, or are you doing it all yourself?

 

I'm doing it myself. But if this turns out nice, I might start taking orders.

 

Thats a start.
Now remove the HVAC, stereo, Emergency brake (its an auto after all), air bags, cruise control, power steering, and front and rear bumper supports.
Thats weight reduction.