Yesterday I drove from B'ham to York and back, 300 miles I guess, cruise control set at 70mph for vast majority of the journey.
My 325D returned 56mpg, aircon off, just me sat in it, no luggage or anything.
Then, after getting home and having some nosh, I went out to Stratford for a hoon with my brother and we bothered some country lanes. Touched 3 figures regularly, had an absolute hoot. Got home and economy average had dropped to 50mpg. City driving it returns 33mpg versus the 21mpg my old 330ci gave.
3.0 litre, 6 cyl, 200bhp, it's far from slow - at a rough guess I'd say straight line speed would match a 200bhp CTR without any trouble (which weighs I guess 150 kilos or so less). Now here's the really funny bit - it actually sounds fantastic when you boot it - 6 cylinder growl and inside the car you hear zero clatter.
There are some superb performance diesels on the market but some people seem to be in denial about it.