Audi-Phile S4

are you sure about that? ok so tell em to get a test pipe instead? what about cel? does he have to get a 02Bung? and what about smog? will it pass?

poppachulo

He could gut his cat if he didn't care about saving it, but it would be like running a test pipe (a test pipe will have better flow than a gutted cat). S4's get away with gutting the pre-cats because there are still cats further downstream to handle emissions.

If he runs a tp he will get a cel, unless he has software to get rid of the cel.

Dunno what an O2Bung is.

Audi-Phile S4

but he CAN gut his cat or no? also a test pipe WILL throw a CEL. so what kind of software are you talking about? and an 02 bung is the same as an oxygen sensor spacer. you get me?>

Allroady DungBeetle

Test pipe will not pass smog and will be minimal if any real noticeable gains with stock turbo.

If he wants more power at this point he'll need either a K04 turbo and software upgrade... or bigger turbo and software.

A FMIC may help a little on sustained hard runs but really the gain is minimal on a street car with stock turbo.

Audi-Phile S4

so if he gets a test pipe its not really worth it becuase he wont pass smog and the gain are minimal on stock turbo, so then its really not worth it. besides the K04 upgrade what may be a larger turbo that he can go with? something that wont lag alot and that is still daily driveable? also if/when he goes BT what type of cat should he get? not a test pipe because he wont pass smog, right? so should he go with a high flow cat? will it pass smog with a high flow cat?

Allroady DungBeetle

Depending on what state you're in a HFC will pass so long as the CEL is not on. Go for K04, quick spooling stock like daily driver with a much improved top end for short $$. Also if you drive it easy there is no "need" to upgrade clutch/etc. For that matter a K04 with a stock cat is not bad at all. The cat is not the restriction in the system so much as the down-pipe and rest of the exhaust.