Wassup FBN long time, well as of late I been thinking about putting a x pipe on my bird. I found all the parts that needed,(That includes another cat) but since I have a v6, and I only have 3 o2 sensors, where would i mount the sensor at? And do I have to get a forth o2 sensor for the new cat? I live in California btw, so I'm trying to make this procedure as legal as possible. Any advice will help, thanks.