I have the Gibson Catback exhaust on my 15 premium six speed. I really like it and the butt dyno suggests a big increase in power. The sound is bold and loud. There is cabin drone in 6th gear around 2000 rpm but I adjust and live with it. The thing with this exhaust is it sounds so mean even at regular economy style driving which is lots of fun. At WOT it rocks. Hope this helps.