What does high flow cat do? I mean the stock cat is 2" id right. so if u put say a 3" id universal cat on the stock cat it would basically be the samething as A high flo cat. Yes or no. probably not but just curious.

Hi flow cat is a replacement to the stock cat for a better flowing exhaust. Yes you could consider a 3 cat High flow but it is more of how the inside of the cat is made that makes it high flow, rather than the diameter. Just like a muffler. Compare it to a test pipe. there is nothing in the center of a test pipe making it flow much more efficiently. Hope this helps.

99GSX Auto 14b@17psi 13.345@102mph