I just read today in Diesel Performance Magazine that they reto-fitted a Jetta TDI with the "Snow" Water/Meth Injector Kit. Before doing this the car on the dynometer hit 151HP and was getting 38 mpg combined. After the install the car was getting 41.7 mpg and 170 HP. Thus, a bump of about 10% in fuel economy and 19 HP increase. Have no idea of the cost of the kit or install but interesting as that would equal the 170 GTD.