If you are going to compete in any form of Motorsport, find a club and read the club rules regarding modifications before lifting a spanner. No good spending big bucks and time building a car that does not fit any of the classes offered or puts you against wildly modified vehicles.
For example, if I removed the door trims from my KE20, I would of had to compete in the specials class at the club I was involved in.
in VIC, if you tan in the PRC class, all you could run was a 3k.