Fitz; air fuel gauge has nothing to do with changing the AF ratio it just monitors
Joe: Yes you can but im not sure which one you need to splice into..I am running a summit racing AF gauge on my scirocco and it was cake because its single wire, but im not sure on these...im useless sorry
but its whichever one is the signal wire
one is heater, one is signal and there are one or 2 grounds..
Edit: oh and keep in mind if you extend or shorten the wires from the AF gauge all the o2 readings will be off unless you use a much larger diameter wire and actually solder the connections on the extended piece so that there is minimal change in resistance, but the original wire that comes with the AF gauge should not be cut