mod it...after ur done with ur fun PART OUT

 

By asking the question I think you already know the answer. Don't bother spending the $ and effort to put something onto the car that wasn't intended to be there Temporary things that may actually make a difference in performance are another story. My 997.2 C2S is being built and when it arrives I won't be doing that much to it other than:

1. Alignment. Should be able to get -1.3 degrees of camber and probably won't do GT3 control arms to get more for a while.
2. Software - Softronic is working on the 997.2 version and the initial reports are encouraging.
3. Primary muffler bypass. Should keep you "legal" and give you a little boost in performance.
4. Possibly intake, though I don't like oiled filters as I've had MAF fouling in the past.

Any of the above are simple "bolt on" and when you return the car to stock before turning it in, nobody will be the wiser. Then you can sell off the aftermarket parts...