Does anybody out there have any experience of chipping a 2007 520d (163bhp).
Key questions for me would be as follows:
Is a plug in device or an ECU reprogramme the better solution?
Is the mod visible when the car is serviced - (dont want to invalidate the balance of the 3 year warranty :-)
If you use a plug in device do you need to remove it for each service?
Do fault codes show up in the car memory?
If fault codes do show up, how do you eliminate them?
Can anyone recommend any particular makes?
All help, comments, recommendation very gratefully received