Hi Dave & Cherie,
My first dilemma is that I haven't yet decided which tuning-box to go for (there are loads to choose from and all claim to give oodles more hp/torque plus better mpg). Some have chosen the basic Racechip box at around £100, alternatively there is a TDI Tuning box at £289 (all of these boxes intercept the data from the ECU at the diesel rail and basically fool it into delivering more fuel or so I understand) There are however those who admonish going down the ECU remap route and a popular method is the Bluefin which is a handheld device that you plug into the diagnostic port of the car, remove the existing map and replace it with a map which you download via the internet from such as Racechip. My biggest problem is that before installing any of these devices, you are obliged to declare the modification to your cars performance to your insurer - mine said it was acceptable BUT whether the device was installed by me or a garage, they would need a document from a certified engineer confirming that the installation had been done correctly before they would consider adding this to my insurance cover - the extra premium would equate to around £36 per annum. Hope I haven't confused you AND I do know that most of the tuning boxes can be self-adjusted to target more mpg or better torque etc.