You can all see the mods I have in my signature, but one thing I dont have is an exhaust. The only thing I have had done to it is the stock resinators, has been cut off and muffler. I have a "ractive" (2.25 in inlet), (2.5in) oulet, muffler right now. I know that the stock svt piping is 2.25in. My question, should I go with a 2.5in piping since I have the CFM 67mm TB? And, do I need to get my car tuned with all of these things added on?