My car is a 2002 1.9TDI 130bhp which has been remapped (by a semi-big company that I don't wish to name). I remapped it the week I bought it so didn't really have any time to compare old fuel economy to new fuel economy. I've done about 20k miles since buying the car in october 2006. Most motorway trips I've seen around 50mpg unless I've been gassing it in which case the very worst I've seen is down towards 40mpg. Driving back from Llandudno yesterday I managed a whopping 61.3mpg average which involved A road driving and some driving around town (total distance about 140miles). I was shocked actually. Since leaving Derby for a weekend in wales I used half a tank (according the indicator in the car) and did about 400miles. It's the most I've ever seen out of half a tank! This leads me to think that an 800mile tank may be possible if you drove sensibly on a long road for 800 miles!
So, what have other people got and and what can one expect?