I am looking for a Hi-Flow catalytic converter. What's the difference between 100 CPSI and 300 CPSI? I have a H22A7 motor with RMF headers and 2.5" exhaust. What do I need to consider when getting a Hi-flow cat? Do I need to worry about back pressure?

 

I'm not sure about those numbers and what they mean. But just make sure you get one that is 2.5" Hi-Flow cat which is one I have with my Hytech Rep Header and 2.5" exhaust piping.