Originally Posted by NecioVato

In the end - I think it all goes back to personal preference. I have the FI exhaust and their HFCs as well. I love it overall but you are right - when I would do road trips - when I was cruising at 75-80MPH; it was really really annoying for long periods of time. For me - the best fix was having a friend hook up to the car and did the following as far as the settings provided:
Turning OFF the sound enhancement
Leaving ON the noise cancelation

By doing that - it winded up making it a lot less 'loud' in the cabin so made roadtrips a lot more bearable. Either that or I'm getting old haha but regardless that helped and now - I LOVE driving the car even more. But if I remember correctly - the Stillen sounded nice and a friend of mine had the Greddy Exhaust which was nice sounding as well. I just was never a fan of the 'single exit' exhaust sounding exhausts - but just my .02 on that haha.