I'm thinking about test pipes with the new exhaust system I'm researching. I've seen hi-flow cats but I wonder why they are a lot cheaper than OEM type. I was told that any exhaust I add won't add more than 15 hp with the stock cats (which I believe). Now I'm wondering if the test pipes will set off the CEL? The car won't be subject to emissions testing due to not driving more than 5K miles / yr. I've driven 32k miles since 2004.

I've seem resonated tp's and plain straight pipes. Anyone use these on a street car? Louder I suspect. Any help on brand names that fit well would be appreciated.
Thanks,
Dave

Yeah I have a borla exhaust also and was wanting to do test pipes but I don't won't it to be too loud bc I like the quite Ness of the borla as of now but I also thought of high flow cat which will give me the most out of the exhaust flow and not be so loud?