my dc5 has full exhaust but still has the cat. i have a test pipe sitting around with the bung for the 02 sensor so if i throw the test pipe in and it does throw a code for the 02 sensor will it actually affect anything? i will put the o2 back in the test pipe

 

No it won't affect anything. Most people with K-pro disable the secondary o2 sensor. You could also buy a o2 sensor simulator and that would avoid the CEL.

 

awesome i found a write up on clubrsx on making ur own looks way easy will be trying it tommorrow.

 

I use to have one myself