i have an i/h/e setup that sounds almost stock, it only roars when i gas it. I just bought a high flow cat, and im wondering if it will be really loud. One time I didnt install the gasket between the cat and the header before, and it sounded like i was running on full open header. Does ne one have a high flow cat, if so how much louder did it get? thanx

 

It will change the sound of the exhaust due to the fact that you have less resistance but it should not be anywhere near annoying. I know this doesnt help much but I think it sounds more throaty and not painful. Plus anything that help performance I am willing to make a little sacrifice in that regard.

 

it will sound better than a test pipe. I have one and love the sound, its not all raspy and ****.