I did use slick 50 in a Toyota mini van I had a few years ago. I'll be honest, the engine started and ran better and was much quieter and my fuel mileage did go up about 10-15%.

Was is all in my head,,,,possibly, but man the stuff sure seemed to work. My dad had the same experience with an old 1977 Ford pick-up that he is still driving.

PS, I don't use it in my 300D and I don't plan on it.

JCD