i have mine done on my 01 gsr. i have 2.5" piping for the test pipe. it made my car sound a little deeper. didnt notice any gain the hp though. its going to be hard to find an exhaust shop to work on it due to not having a cat is illegal. i needed some exhaust work done and i cant find a place to touch the car. let me know if you do find a shop that does it.