[jflogerzi]

Originally Posted by Jesse@JDLAutodesign

The high flow spun metallic cats are not very restrictive IMO. They will still make good numbers. I have a catted UEL here, has never been tested or posted about, weren't sure if we wanted to pursue them. The cat required for it is more expensive than the one used in the EL header, the runner layout is also quite a bit different than our non catted UEL. There's also no absolute guarantee that you won't eventually throw a CEL on stock tune nor pass emissions in places like California. Basically we weren't sure if the price increase could be justified with the only guarantee being maybe passing a visual inspection and reducing noise/rasp.

You would never pass smog in CA as replacing any cat with anything but OEM would cause you to fail.