when i went down to the local muffler shop to get a carsound hi flow cat , they were installing it and they were going to put the o2 bung in because i have a 98 gsr but they said my o2 sensor was stripped or something, how could I get it in or do I have to buy a new one? where could i get one for cheap? also could the o2 sensor be bad since it has been just hangin their outside? thanks in advance