Its different for each car, some cars have alot more then others, But engine/suspension stuff is all modifiable , the have taken it to the next level in this you can even get different tail shafts and everything.
ae86 wise you can have either 4age, 3sge or 3sgte or u can turbo or supercharge any of them. body wise there is just a forza body kit for it so just adds diffusers to the original body kit.
other cars have full after market kits to put on
