First here the problem. My motor B18c1 motor is in the shop for a overhaul. I just bought an Apex-i N1 exhuast system. My friend wanted to use my other exhuast system on his 97 LS. It didn't fit because he was using a header he bought of ebay with a 2.5" collector. So he used my gsr header, hi flow cat, and full catback. now is check engine light is on and i thinks is because of the hi flow cat. one of his O2 sensor is behind the cat.

The question is
Does any one know where i can find a hi flow cat for a OBD2 or is there a way to get around the check engine light via messing with the ecu?

 

Magnaflow.com. these are 50 state legal cats.