CEL P0420 Test Pipe / HFC - Non-foulers

[omg35s]

My shop installed GTM RTP's on my 2007 g35s and unfortunately even with the extended o2 J-Bung my car is throwing CEL P0420.

I wonder why it's throwing only P0420, which is the passengers side and not P0430 which is the drivers side?

Berk and GTM were kind enough to explain that both these codes do not affect performance.

Berk has recommended to use stainless steel wool and maybe purchase non-foulers. Where is everyone buying these parts from? Links are appreciated.

Anyone else running this code with their RTP/HFC? What was your solution/experience?

I was also worried that maybe my o2 sensors were bad so I pulled some live data from my OBII scanner:

O2S B1 S1 (V) 0.445
O2S B1 S2 (V) 0.280

O2S B2 S1 (V) 0.900
O2S B2 S2 (V) 0.290

Does this look right?

Thanks!