I ordered an AquaTune for my '90 VW Vanagan Suncro with the 2.1L water-cooled engine and had my mechanic install it. Needless to say my mechanic was quite impressed with the results after this installation. When I came to pick up the vehicle he told me I gained every bit of 30% increase in hp. As he puts it, it definitely gave it some big “kahunas”. Of course, after driving it myself, I am in total agreement with him. This is why I am placing my second order today for an AquaTunePlus for my '90 Audi Quatro. Your happy customer in New Jersey, R. D.