Carefull munchkin, you have me confused with someone else, I would not suggest some mod I have not tried myself, and I have not done the X, only the H and have been happy. I could only verify that others have said it works, I dunno if that is true. Are there dyno #'s that say something, and what cats and muffs are they using to get the result. You don't want your car to sound like a Shelby 500 with it's Chinese New Year exhaust.