CA emissions for 2014 Jeep Cherokee Sport 4x4

I need to replace the Manifold/Cat combo on my 2014 Jeep Cherokee sport 4X4. It was built for California emissions specs as I purchased it in CA but since I now live in TN. will it be okay to get a cheaper aftermarket manifold/cat to install or do I have to go OEM? One mechanic here in TN told me if I put a cheaper aftermarket one on it will keep throwing codes and check engine light, but I don't want to spend $1600 on an OEM man/cat.

 

Are there any codes or CEL right now with the bad OEM exhaust system? Depending upon what makes your Jeep CA compliant versus the rest of us the mechanic might be right. For example if the engine has multiple O2 sensors and you install a non-CA exhaust system that has fewer O2 sensor ports the computer might be looking for the others triggering a code(s). Check out Rock Auto to see if there is an aftermarket exhaust system kit that replaces the entire CA exhaust system. I purchased a complete Walker exhaust system kit from Rock Auto and it passed my local DMV emissions test. It was not as robust as the OEM but it was under $500.