I have read it but have to say that the bmw's are working on an idle, full throttle and cruising temperature thing (if I recall correctly which is set at certain temperatures.) By manipulating this via changing from the recommended 50/50 ratio to the advised 20/80 ratio you will lower the temperature (possibly) inside the engine and thus will make the temperature sensor sense that the coolant is too cold and keep the car rich in fuel (like what it does during cold start) and waste fuel. Dont you think so?