I have two TT's, one had a Borla on the car when I bought it. I was talking to Greg one time and he mentioned the Borla was the worst. So next time I was under the car I looked at it and boy was he ever right. I did like the sound of the Borla, but for performance really bad. Also I don't know why but the steel gasket between the mid pipe and cat back was 2 inch. I now have a 3 inch Specialty Z cat back and it made a huge difference in performance. It is a bit loud but for daily driving I like it. On my other Z it has a Specialty Z 3 inch down pipe 3 inch to 2.5 inch mid pipe, and a 2.5 inch cat back, all Specialty Z. This is great power and just right for longer drives i.e. not too loud or droning. Some day I may buy resonators for the 3 inch cat back.