Managed this on 140 mile round trip, M1, M25 and M40 back not in any rush but to see a IS300H Luxury in Grey for my father in law. (another soon to be owner :)) I am a little suspicious though as when I was in the Car mode on the Infot screen I selected Update and the MPG on the instrument panel seemee to be changing Real time rather than averaging out. Odd or maybe not?