The diesel X-types will return roughly 42-48mpg in general. The 2.0 is slightly more frugal with the fuel. I have the 2.2 and I get roughly 44-46mpg which I consider pretty good. On a run, they will do more obviously, but don't expect 60+. You'll get around 55 max on a long run. Mine has been chipped and still returns pretty much the same mpg as standard, despite it being much easier to stick the right foot down, there is little need as it now pulls superbly without hammering the throttle. If you buy either the 2.0 or the 2.2 and expect to get around 50mpg on a motorway run and an overall average of around 40-45mpg you'll not be disappointed. The real choice here is whether you want the refined, smooth unflustered 2.0D with it's 5-spd gearbox, or the entertaining, brisk, driver focussed 2.2D with the 6spd box. The fuel use will be much the same with either.