5,500$ OBO - motivated to sell so don’t be afraid to inquire about it

Been working on getting this car ready to sell because I joined the trades and need something different, but have a problem with the emissions. Getting the code P0420, even though I’ve replaced catalytic converters as well as headers and internal engine gaskets. Don’t have more time to work on it so I just want to sell. Could be something as simple as crappy gaskets or bad sensors. Car runs great besides that one problem.