circuit werks or Blackhorse cat backs?

[NewArt]

You will most likely get a cel if you switch to headers. The secondary cats will require a long O2 sensor lead to reach the downstream bung. My Circuitwerks high flow cats threw a cel for insufficiency. You would then need a tune to eliminate that. You might watch some of my videos which deal with these things.
The Porsche as seen by NewArt

[aparke4]

For what it is worth, I have the circuit werks 2nd cat delete on my 02 S, no code issues and have seen a few muffler cat back kits and they seem to be quality. My 2nd cat deletes and U pipes to muffler fit great and welds were very nice. Also, they are out of TX/ USA!

I would recommend them and there are some bosch o2 sensor extensions that you can make if needed as well.

[NewArt]

Originally Posted by aparke4

For what it is worth, I have the circuit werks 2nd cat delete on my 02 S, no code issues and have seen a few muffler cat back kits and they seem to be quality. My 2nd cat deletes and U pipes to muffler fit great and welds were very nice. Also, they are out of TX/ USA!

I would recommend them and there are some bosch o2 sensor extensions that you can make if needed as well.

Yes, a secondary cat delete won’t throw a code if you’re running stock headers which have the primary cats integrated in North America.

[jaykay]

Originally Posted by NewArt

You will most likely get a cel if you switch to headers. The secondary cats will require a long O2 sensor lead to reach the downstream bung. My Circuitwerks high flow cats threw a cel for insufficiency. You would then need a tune to eliminate that. You might watch some of my videos which deal with these things.
The Porsche as seen by NewArt

James,

You answered it here apologies. So do you think some other make would not throw a code ie if they flowed less?