Unfortunately, since your RT is still under warranty, you have to be very careful what if any mods you do to it. There is a lot of secondary information and mis-information being posted on various blogs as to what you can mod and still be under warranty. But, the bottom-line is that once you start modifying a new car you risk losing your warranty. I have read, that any part, read that as a factory Mopar part, that your dealer installs is then covered and will not affect your basic warranty. The best advice I would give is to stop by your local dealer and ask. On the other hand, if you could care less about the warranty, then only the size of your wallet becomes the limiting factor. Also, if you are serious about performance, get yourself one of the hand held tuners as you will have to give your Challenger a “super tune” sooner or later………..