Creative use of expanding foam...

Check this out, not Celica but interesting idea for making a custom body kit...

http://justsomething.co/old-junk-car/

Now use the finished foam design as a mold for fiberglass (like the guy in this video) instead of just leaving it on your car and you don't have to worry about excess weight.

https://youtu.be/UHdJYL7iiRk