I have the money saved to do my exhaust but all you guys say that the y-pipe does not fit correctly. What will I have to do to make that work and how big of a pipe from the headers to over the rear can I run? I am willing to run a whole new exhaust but would rather keep my flowmaster exhaust and muffler. HP of my car when tuned will be between 500-600 flywheel. I will also run nitrous (up to 300 RW).