I also run the Bassani X with hiflo cats. I love the sound (it was VERY loud the first day and then progressively got more tame but still more aggressive and louder than stock). However, my question to others who run the X pipe is if they have any problems scraping it while driving? It seems to stick down more than the stock H pipe and I find myself scraping it on road humps (big, wide speed bumps) and other semi-abrupt changes in the road surface that I don't think should be a problem. I haven't lowered the car in any way, although I want to eventually but now I'm afraid I'll rip the exhaust right off on any little bump!