You can go to the global BMW site and download the full product brochure (but for non-US spec cars)…
Go to
http://www.bmw.com/ select X6 and find one of the downloads (the 4.46 MB PDF download is the full catalogue).
The European catalog for the X6 clearly lists towing to be:
Permitted trailer load, unbraked – 750kg all models
Permitted trailer load, braked, max. 12% gradient – 2,700/3,500kg (where 3,500 require some ‘special option increased trailer load’) for all models except the 50i.
Permitted trailer load, braked, max. 12% gradient – 3,500kg for the 50i with no ‘special option’ required.
Same listing for 8% gradient.
No big surprise – these are EXACTLY the same numbers as listed for the X5
Sadly, the European catalog does NOT show the trailer hitch itself as an option… so I guess it’s totally a DIO (Dealer installed option). I was really curious about where the hitch protrudes from the rear bumper area. The tail is so high on the vehicle, I’m guessing the hitch is actually below most everything…
Cheers,