Mustang GT o2 sons or and others on 300 e
 

I have seen that some have used ford 5liter oxygen sensors on their m103 engines I have tried one from a 95 Honda civic that recently went to it's final resting place It is a 4wire sensor that draws 8amps in the heating circuit. The Benz draws 12 or 15amps I can't remember . The Benz sensor has 3 wires I Splic Ed the heater wires to the oem plug observing polarity as found on the civic sevice manual for the Honda sensor. The extra wire is ground for the sensor. I grounded it to chassis as the benz one gets ground via the sensor housings connection to chassis when installed.. The sensor wire gets spliced to the sensor wire on the oem plug
It has been in the car for a couple months and seems to work ok

You have to make sure the white heater wires are in order. They are the same color, but if you put them in backwards, the heater won't work.

FYI to others. So you need to check operation of the heater BEFORE you put it into the exhaust bung.