Hey - I just bought a 2000 S4 and love it - now I'm addicted to speed. Has anyone had problems with emissions control after modding? I live in Washington State, but I suppose this would apply to just about everyone...

 

As long as you do the mods right, you shouldn't have to worry about a MIL light which is all we check for where I live on a 96 or newer car. Not sure about washington though.

 

Thanks! Your S4 looks just like mine Now to get it similar under the hood!

 

You didn't say what you are modding.

If you remove the cats, you will get a cel light. Keep the main cats, remove the DP cats right after the turbo. That's the only
real restrictive emission component.

Most stuff will be ok, really the car runs really clean already. So don't remove the cat, and leave the other stuff alone.
There really is no big performance gain with remove all the emissions stuff, besides the precats.

 

Nothing crazy I think - Going to start with the exhaust and then chip it. About $1500 is all I can really afford right now, so this seems like a good way to start. The R03 turbos were replaced by the previous owner in January, so I think they should hold on for awhile anyhow...

 

Should get you a good start, the first jump in horsepower is pretty cheap. From there on out it gets expensive quickly.