I've got a '02 A4 Quattro 3.0 and I'm going to replace my O2 sensors. My problem is that there are 2, 3, 4, and 5 wires sensors. How can I determine which is for my car without removing them before I got replacements?

 

Here is a Stage 3 install DIY, but there is some info about 02 sensor, just search for 02 sensor on that page, thats like a little bit above the middle of the page http://a4mods.com/index.php?page=web...ages/apr3.html