Beware of the cheap chips. There are quite a few advertised that say they do a lot of the same advertised results- and all they really are is a resistor to make your car think it's colder outside. If its' an easy 2wire hookup, it goes to your A/T sensor- that's it. Colder air is denser, so your computer adds a few percentage points worth extra fuel. Read the book, make a few choices, try them out yourself. It works on my 528e, as well as my Goldwing and my wife's Taurus LX POS.There ain't no miracles.