I have an SD having previously had a 535d...mine was delivered before Christmas. Very,very happy with it. Feel free to ask anything specific.

Your car may have been brought forward because there is a problem with M Sport production, that's just a guess.

On the subject of depreciation, I just don't think you can expet anything except heavy depreciation from new cars now. BMW is a volume manufacturer, stated aims are to grow volumes considerably so don't expect it to get better. Don't let it spoil your enjoyment of the X5 though! It's the same for all manufacturers. Having said that my 535d retained 63% of the price I paid for it new which I think is excellent over 3years (it was low mileage but that doesn't get you much credit come trade in).