I installed the Borla Cat-back exhaust system plus x-pipe today, the offroad version. I was thinking at first, oh damn what did i do and thought it would be rediculously loud but no.......and DAAYYYYUUUMMMM does it sounds good. Pretty sure that Borla installed my own personal cheerleaders in the pipes. It sounds deep and throaty. I stuck my car on the dyno before stock today and it produce 344rwhp and 318 torque, after it produced 354rwhp and 326 on torque, it was a hot day down here though and not much airflow. I forgot the printouts for the dyno but will pick them up early on in the week when i go back to get the k&n system installed.