do all test pipe need cel fix or just some?

 

All need it if you're putting it on an OBD2 car. Some come with it.

 

if i am driving an AP1, and planning to decat, what should i do so the CEL dont come on?

 

This will solve all your problems. Takes minuites to install and the CEL will simply turn off, no need to reset the ECU. When I installed mine, I drove the car for 5-10 min and the light just shut off and never came on again. It did it's job well.

Here is the link
BLOX CEL Eliminator

 

It depends on who you buy from. My pipe came with the mechanical sim.

 

i thought there was something called anti-foulers that made you not get CELs

 

BTW I managed to get an 08 to not throw a CEL.

Two Spark plug defoulers, first one (closest to the TP) stuffed completely full of steel wool. Pack it in there good....

1k miles so far