I have a 2014 dodge journey 3.6l SXT AWD showing code P0420. I swapped both upstream and down stream with Bosch O2 sensors and it spit out more codes. Thanks to the forum, I found out that the NTK O2 sensors were best so I swapped the Bosch ones out and replaced with the NTK's. It went back to the P0420 code. I finally took it to a mechanic shop and they told me that I need a new catalytic converter. I was given two estimates, one for a genuine Mopar cat and one for an aftermarket. I saw online that Dorman makes one for $350 and the dealer wants $1,800 for a genuine Mopar cat. My question is: if I install the Dorman aftermarket will it continue to set off the P0420 code or do I need to buy the Genuine Mopar cat? I live in Virginia so there are no emissions. Anyone have any suggestions?