I've had 15k in my crossfire and I've had my magnaflow since 3k. I didn't notice any difference or change of sound at all since I got it and I've fixed the problem about others complaining that it's too loud by adding more insulation around my doors. It also fixed the problem about my door popping and wind noise. Im very much happy with it as of now and I'm still waiting for a true exhaust muffler that can add more HP to our crossfires (I don't think Borla claimed more HP increase with their exhaust).