You gotta crawl under to find it. There is a plug in the down pipe for diognostic use. (measuring co before the cat) The o2 sensor lives just about center of the exaust manifold, hidden by the turbo. ECU lead to the sensor comes thru firewall, pass side. Usually hides behind a heat sheild, then goes toward the head. O2 wire usually found wire tied to coolant pipe as it rounds the corner behind the engine. By the way, the sensor mounts vertically.