I currently have roush axle backs on my 2012 gt with the factory exhaust. I am looking to pick up some more power. Losing the cats IS NOT an option. From the looks of it the factory H pipe is pretty restrictive. So I was looking at the BBK X pipe and also the heart throb H pipe to the axle system. I would prefer the H pipe sound, but sound isn't as big of a deal as horsepower per dollar here. So what are your opinions on this? A $169 X pipe or a $469 system? As far as other power gainers I have, an air raid intake, bama tune, 3.73 gears and some sticky tires for the track.