I have a 2002 S that is slightly modified from stock ( head work ) . Jake Raby is in my back yard so I have been dealing with him on the slightly modified heads. When he had a used exhaust system available I purchased it. This used system was a set of aftermarket headers with attached high flow cats not sure who the manufacturer is. Jake also had a Dansk performance banana muffler that I purchased. So we removed the OEM exhaust which had four cats and replaced with a " high performance " system with two cats and bypass pipes. Jake was very up front that this was not going to make huge gains but would make a difference. We had dyno data of before and after and if I remember correctly we made about 5-7 additional horsepower. So we made some extra power, decreased some weight and improved the overall sound. Am I happy ? You bet. Did I gain 20-30 hp as some would claim ? Not even close but in reallity I never expected that type of gain. Lets face it Porsche did not leave a lot on the table for bolt ons to make a dramatic increase. But a little here and a little there adds up. I really can't see a better exhaust than what I currently have. It is not intrusive, has ZERO drone and has some bark when you rev her up. Plus it's lighter than stock what's not to like ? I just need more power

but Jake and I are working on that also.