Header options advice needed

[NewArt]

Having upgraded the intake/throttle body side and just having had a custom tune done, I’m now considering some exhaust mods. At this point I have stock headers/cats, secondary cat bypass and stock muffler. I’m currently getting a CEL due to bad cats. I tried changing the O2 sensors but my Durametric tels me my cats are operating below spec. So... Do I replace the bad cats with stock? Do I try to find some 200 cell cat/headers? Do I put on catless headers and put my secondary cats back on with new bungs welded on for the O2 sensors? Or what else?
I am not interested in changing the sound. I track this car but I do use it around town so I don’t want to make it much louder. Any wisdom would be much appreciated!