So far all I know is the AC needs to be removed, New headers and crossover need to be installed, and custom downpipe made up. Is that it?? Im just concerned about the headers and where the turbo location is going to end up. Ive already removed the AC. I would just hate to spend 3K on heads and pipes and then still have to fab the new headers or fitment issues. If you are running either one of these heads on your TTA please tell me exactly what needs to be done. Also was it worth it? Im not competing with this car either so unless its a noticable gain of performance Im not going to waste my money on them.