I have a Milltek Cat back, but my sports cat and downpipe were made my Janspeed. Made to a very high standard and the difference in performance is very noticable, even more so when the map was changed to take into account the easier breathing. Car has a very raspy note over 3k rpm and its tubed nicely so you hear the turbo spooling up. not to everyones taste and you certainly know its coming down the road, but then I only use it at weekends.