I'm new too, and just bought a 2006 318i If you look in adds on autotrader they usually give you the town, motorway and average mpg. Mine is supposed to average 37 mpg, but as I travel mostly on the motorway I'm hoping it'll do a bit better than that. We'll see!! I was advised that the crossover point is around 10 to 12 thousand a year to make diesel worth it, but that depends on all sorts of other things too. I switched to a BMW from a diesel passat as it was about to cost me a grand for a new turbo and my two favorite garages both recommended them as more reliable.
