I have my 3.0d (184hp) ecu remapped to 220hp and 490Nm. Before I go to the dealer for something serious, the tuningshop just puts the original data back and after the visit, the remap to the tuned data. All free of charge. The dealer by the way knows about it, and even if I would forget to set all back to original, they just overwrite it. Hell, they even told me where to go to get the car tuned....