Service Engine Soon - HFC/TP o2 Sensors (P0420 & P0430)

omg35s

2007 Infiniti G35s 6mt Sedan

Inspection is coming up and I need some advice!

Exhaust set-up = Stillen Catback Exhaust with GTM Resonated Test Pipes.

Car is throwing codes P0420 & P0430, which is common for HFC/TP's. My GTM RTP's have the extended J-Bung for the rear o2 extenders but it didn't help and my car still throws the codes.

I put in some steel wool (2" long 1" diameter) into the J-Bung yesterday and it still throws the codes. It didn't take that much force or effort to insert the steel wool but it did seem rather secure? I'm thinking about adding some more steel wool? How much is too much and how little is too little?

I can't add any extenders because there is no room due to the already extended J-Bung of the GTM RTP'.

Seems like my options are going back to stock cats if the steel wool doesn't work?

Anyone know of any friendly inspection shops in NY?

Thanks!