I have been reading a lot of the exhaust threads and i hear a lot of people talking about high flow cats, and using test pipes and i understand the benefits. the problem is that at the moment i can't ecu and chip tilll i can re register the car in Michigan. so im wondering if i will have an issue with the secondary o2 sensor if use either a high flow cat or test pipe.

 

I have a high flow cat delete with the o2 sensor plug for sale Megan racing Brand new in box 80 shipped