Someone told me that there was a 3.25inch inlet/outlet cat available for our cars and it should produce more hp/tq compared to the kinetix or crawford cats with exhaust system and unichip. Is this true? I know kinetix cats are 2.5" inlet/outlet but is 3.25" better with my borla exhaust (2.25inch piping)? I would imagine that if I get the 3.25" that I would have a lot of back pressure.

Any comments or thoughts would be helpful, thanks.