2005 BMW X5 4.4 and I get a little under 19 mpg in combined city/highway (cruising around 70mph) On long trips it gets around 20mpg or a little better. I have an 2002 BMW X5 3.0 and it generally gets 1-2 mpg better. I feel like it is not that huge of a difference and i enjoy having the extra grunt of the V8!!