A word of warning for anyone who has had a Brabus chip fitted by a main dealer. My car developed a flat spot recently which was diagnosed as a faulty Brabus chip (D6 III). My dealer wanted to change it under the car's 3 year manufacturers warranty because, as a dealer fit part, it was covered. I had to confirm that it was dealer fitted because there was nothing recorded on the MB Central database, though it wasn't clear why. Before I bought the car in January I'd done a bit of digging (as you do) on service history etc. and wrote notes at the time. Referring to these notes I determined which dealer supplied the car to the first owner and I contacted that dealer to confirm that they had fitted the chip at PDI. They did confirm this and produced an internal invoice where Service charged Sales for the fitment. However, MB Warranty wouldn't accept this. It appeared that they would only sanction a replacement box upon receipt of an installation certificate that original dealer should have filled in at fitment time. It's a four part document with copies to the owner, Warranty, dealer and Brabus. To cut a very long story short it has taken me two days of continual liaising between three dealerships to eventually get a replacement installation certificate acceptable for Warranty to sanction the new box. They weren't interested in the supplying dealer's internal invoice and the service manager of the dealership confirming beyond reasonable doubt that they had originally fitted the chip. It's to do with the certificate confirming the chip was fitted by a Brabus trained technician. At one point there was total impasse, with me caught in the middle and my car in the dealer going nowhere fast (no pun intended). So, if you've had a chip fitted by a main dealer or now own a car with a dealer fitted chip, get that certificate, or if it fails Warranty don't want to know (even though in my case I'd got the supplying dealer's internal invoice and my local dealer's service management on my side). Whilst I'm told it's rare (??), the supplying dealer didn't issue the certificate and didn't record the fitment on the MB central database. This left me, the customer, trawling round the dealer network trying to prove it was dealer fitted, and the whole saga has wasted two days of my time. If you want to PM about this for more info, please feel free.