So we have to get the state inspection done on my car, and because of the CEL it would fail. So we went to Advance... All they had were Bosch Oxygen sensors in all the stores within 100 miles (ugh). So ended up getting them. Made in USA. The rear O2 sensor has never been changed, so I'm hoping changing it will keep the CEL for Catalyst efficiency off. The only thing I'm concerned with is that I hear lots of stuff about bosch products, O2 sensors included, not all of it good. I replaced both o2 sensors. Anyone have past experience with them?