Originally Posted by dpazz
The specs state 34mpg for my current car and I manage 30mpg average. But if it's 100% motorway I can hit 36mpg easily.
Is that the NA or turbo GTi? Why I ask, if it is the turbo I'd suggest (purely on experience from mpg figures for engine types) that you will likely find it hard to get high figures in a 320d. For two reasons, being frank here, either your conditions are quite average, or you don't appear to drive economically, even on the motorway. Also coming from the GTi I suggest you will work the diesel, to get performance.
BTW, recent London to Brighton run had the BMW 320d @ around 77mpg.