Okay, so I've searched google, VWVortex, and Audi Forums for info on a DIY for piggies for the B6 model s4. I know how to remove the downpipes (found that thread)
So I can remove the DPs and I can gut the precats. But from there, I'm just no connecting the dot with the CEL and the O2 sensors. I understand that there are 4 O2 sensors? 2 after the precats and 2 after the main cats? Do I simply buy a set of spark plug defoulers and put them into the openings for the precat O2 sensors? Do I have to move them closer to the main cats AND space them?? Should I get the VAST spacers instead?
I've read that you sometimes will get a CEL anyway, even if you space the O2 sensors.
If I go to the trouble of pulling my DPs and gutting them, what do I need to do to the sensors to avoid a CEL?
I gutted all 4 cats. I installed the VAST spacers in the rear-most 02 sensors. No CEL. Dont need to extend any wires. Just plug and play. Big difference