Just had the Mustang on the dyno and found out I am running very lean. I had never been outside the car when someone else was hammering it. And it seemed to run fine. But when the guy stomped on it as I sat aside listening, I could hear it stumbling, and the print out showed the proof. Need to buy a tweecer, but want to get a air/fuel gauge to monitor it. I need to know what gauge you use and the pros/cons. I am looking at this set up DB Gauges: Air Fuel Ratio Guage but don't know alot about it ...yet...