I too have a custom made stainless steel exhaust system under my S6 C4 2.2t by a manufacturer here in Holland. Since I use the S6 as a daily driver I wanted it to sound reserved so that the exhaust note doesn't bother me on long drives, and it has worked out nicely. If you go the custom exhaust route, be shure to have 2 silencers fitted. I stuck with 2,75 inch since that was the largest size that company had a flat silencer for to use in the middle and I used a 200 cpi sportscat. So in conclusion I have:
- Virtually no annoying sound in the drone range.
- A nice 5 cylinder growl above about 3000 rpm.
- Much better spool up from the turbo compared to the original Audi exhaust line.
- A lifelong warranty on the exhaust line.
- The exhaust line is not the lowest part on the bottom of the car anywhere, so no scraping risk.
I would like to add that our S6's are very well isolated against sound and that if you have an exhaust line whose sound bothers you while driving, that it will surely bother 90 per cent of the people you drive past. Unfortunately, not everyone is a petrolhead...
- Virtually no annoying sound in the drone range.
- A nice 5 cylinder growl above about 3000 rpm.
- Much better spool up from the turbo compared to the original Audi exhaust line.
- A lifelong warranty on the exhaust line.
- The exhaust line is not the lowest part on the bottom of the car anywhere, so no scraping risk.
I would like to add that our S6's are very well isolated against sound and that if you have an exhaust line whose sound bothers you while driving, that it will surely bother 90 per cent of the people you drive past. Unfortunately, not everyone is a petrolhead...


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