I have pacesetter headers and the D/P from exhaust depot and I was throwing the P0420 code only. I was trying to get the spark plug antifouler and the O2 sensor in the D/P but it wouldn't fit, the O2 sensor hole and the frame are to close to have both put in, I can only get the O2 senor in. Would it work if I put the antifouler and the O2 sensor in the header together to get rid of the CEL code?

Thanks

Also, for you Marylanders out there who got a HPtuners or trifecta tune to delete the P0420 sensor, did you still pass the emissions test?