Design and performance program help

I have a 1999 Chevy Camaro and im looking for a program where you could install and see the expected results without having actually get the item and dyno your car. I would also like to know if some1 could tell me a program where you could see what your car would look like with body kits or different rims and such.

there is a program ive seen called dyno sim that lets you put together engine combos and see an actuall dyno page of the approximate performance of that combo.
i don't think there is a specific program to test different exterior parts like body kits and rims. photoshop might be your only option for that but it does take some skill to use.