Eric_Oz_S2

Deleting cat on my s2. Is there any potential downside (or benefit) on replacing the pipe between header pipe and cat-back with a larger 2.5" section (test pipe or resonator) if the cat-back is 2.25"? Car is supercharged.

Thanks

Dougs951

Would address the entire exhaust as a system. If you go new stainless you should save a few lbs too.

Eric_Oz_S2

Yeah I did think that, but it would be a shame to throw away a perfectly good dansk cat back.

Kerry Chadderton

The only drawback I had was the terrible "raspy" exhaust note. I switched from a test pipe to a resonator but that didn't remove all of it.

Other than that backpressure was reduced and my EGT went down a bit. Go for it!

V2Rocket

If the catback is smaller then no, there's not really any point to do such a thing.
If you have the parts already, I'd use them, maybe it's not ideal (changing down in pipe size will affect flow, even a little bit) but probably not enough to make a big difference.