So I had been looking at exhausts for my Z and believe the J2 might be the one for me. It looks somewhat stock, sorta lol. I already heard the build quality on this thing is good. Ive also heard a sound clip of it. But I cant seem to find much on this exhaust honestly other than that. So im just wanting anyone who has had this exhaust to chime in on their opinions on this exhaust: noise level compared to stock? Drone both city and highway. And last but not least the butt dyno gain felt; how much more responsive will the CR-Z feel compared to stock? Any/all input is appreciated!!