Will the AEM UEGO sensor bolt up in the stock bung on the downpipe? Im interested in mounting one if I can do it in a way that doesnt require welding another bung on the stock header.

 

Yes it will fit in the stock bung.
But does your engine management allow you to run without the stock O2 sensor?

 

Im on a stock ECU, I thought these things had a narrow band output to connect to the stock ECU? At least this is what ive been reading on the forums. I dont see a point in running 2 O2 sensors if one will work.

 

Stock ecu needs downstream ... or will run like crap.

 

Im just talking about the primary.

Edit. I should clarify. Im interested in a wideband to monitor my AF ratio. I was wanting to use the AEM UEGO sensor to output to the stock primary O2 input so that I dont have two redundant primary sensors side by side.

The secondary would be left alone and , from what ive been reading about it, it doesnt affect how the car runs - just monitors the health of the catalytic converter.

 

Yes some sensors do have a narrowband output, if yours do then yes it could replace the stock one with some wiring changes.
Given the somewhat unreliability of aftermarket sensors I would seriously consider welding on another bung before the cat.
If you take your cat section off it should be a pretty easy job.
You are correct about the secondary sensor, does not affect the car at all, it's just there to monitor the cat efficiency.