i'm in the market for the Primary O2 Sensor off of a 99-00 EX/SI. They are the same part on both models. The primary sensor is located before the cat. converter on the exhaust manifold. If anyone has one in good working order with low miles at a resonable price..then post your price and pm me your contact info. I can get it at the dealership at a discounted price but I'd like to see if i can get my hands on a used one for a fraction of the cost. Thanks