I stumbled upon this product about a month or so ago. Since then I have been using it in my 1985 Mercedes-Benz 300SD at every fill-up. This is a well-kept and good-running car and is my daily driver. But Star Tron® has made it even better! It's so quiet I can hardly hear the engine anymore and my mpg has improved by about 3 to 4 mpg! Finally, and this to me is probably the best part, exhaust smoke is virtually been eliminated! Feels like a much newer car. I've purchased Star Tron® twice from a local marine store,
         - Great product!  R. Fontenot