P0420 eventually returned after about 3-4000km. P0430 gone.
If I did this again, i'd use an ultrasonic cleaner. My method lacked sufficient agitation, imo.
That said - I read in @J1000 's thread that these $200 MangaFlow 334006 hiflo cats pass the ECU checks in 06-07 100's, and they're CARB...