I still drive mine like a petrol and use ALL the available rev range. From standstill I tend to change gear at around 4.5K RPM or close to the limiter which seems to be higher than this. Cruising wise I use 5th gear for speeds from around 30mph upto around 50MPH as below 50 in the octy 6th is useless, for faster speeds 6th is perfect. Changing below 3k means the turbo gets little use and I dont think you will be experiencing the full effect of a TDI engine, with an SDI (non turbo) I can understand changing at that engine speed.

For flexibility, something above 2.5K revs. I don't like to hang about anyway, so that helps.

Driving on A or B roads, where acceleration/braking/cornering is required, I'd adopt the approach above.

If stuck on the M25, I tend tootle along at whatever the lorries can manage. On the flat, with a lorry a little way in front, I use the lowest revs the car feels happy at. MPG goes sky high when adopting this driving style. Obviously, I drop it down the box when acceleration is needed or I encounter a hill.

One of the positives of a "performance diesel" is that if the traffic's bad, it potters around with no vices and I can play the MPG game. In the Impreza, I normally end up contemplating abandoning it at the side of the road and going for a wander in the fields if it's caught in bad traffic.

J.