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4 bungs in a non catted header do nothing for you. The engine ECU cares about the first set, as it uses that to control the fuel mixture going into the engine. The second set are there for OBD II diagnostics to detect catalytic failure (or in this case, cat removal). This is why you should get a CEL if you simply plug all 4 into the non catted header. You can possibly get by with a spark plug defouler, which moves the tip of the O2 sensor out of the exhaust flow somewhat and on some cars will cause the secondary O2s to read "normal" as if they are seeing catalyzed exhaust.
Relocating the secondary set to after the secondary cats may work, but you are going to change the impedance of the circuit with the added wiring. In my case, I also do not have secondary cats as I have the FabSpeed system.
I am VERY surprised you have not gotten a CEL on your car yet.
Patrick
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