My 320d is doing over 62mpg on a run at 80mph

averaging at 42mpg during the week

its pretty amazing what can be done with the diesels, i love playing with them, mines running almost 2 bar of boost aswell

You can see the typical power and torque increases here

http://www.evolutionchips.co.uk/Vehi...ng_Search.html

And a fuel saving of up to 20% is normal.