Sorry to hear about your story...seems oddly similar to mine.
I have an '08 4.8 with around 32K miles on it. Since day one, it's been nothing but trouble. Battery issues. Transmission issues. A minor engine issue. Sunroof issue. It's been one thing after another. Currently I'm having a noise issue that the dealer can't seem to figure out. It's been extremely frustrating. Trying to figure out what to do next...should I just keep on dealing with it or get rid of it? I don't think I would get another BMW after this - and they have been my last 4 cars.

__________________
2008 X5 Sapphire Black 4.8