[elwesso]

Correct me if I'm wrong, but since there's effectively nowhere to put the rear o2 sensors, the ideal situation would be to remove them all together? Otherwise you just have them dangling somewhere... On the euro headers there's only the spots for the front o2 sensors.

I see what you're doing though, basically you're using a resistor to modify the input voltage to get to a corresponding output voltage... I'm not terribly familiar with how these particular o2 sensors work, but the ones I'm familiar with operate in terms of duty cycle. I don't think you can do that and get good results, because the o2 sensor still needs to see that proper heating cycle and needs to see the temperature inside the exhaust stream. I think your idea would work if you wanted to install those sensors on the euro headers, but that kind of defeats the purpose here.

I wonder if you could somehow piggy back the front o2 sensors and use your method to basically step down the voltage and send that to the rear sensor harness..

The ECM doesn't look for a certain voltage, it expects the voltage to fluctuate with the front o2 sensors.. I believe that the front and rear o2 sensors are essentially the same sensor (except with maybe a longer harness)..

Since we're not eliminating the cats, seems fair to me to try and do some trickery, and would seem you could make some sort of little "sorcery box" that you could plug in the factory connections.