I've been considering this very thing quite a bit. Someone in this forum mentioned they sold their X5 after 4.5 years and was able to get 30K from the dealer toward a trade in. I could do that, then take advantage of the new tech and diesel technology at that time.

But if the car is running good with all the options why not keep it. The resale value of a high end vehicle like the X5 after 8 years would still be around 20k i'd imagine and would depreciate at a much slower rate. Who wouldn't want the X5 and all the options for such a price.

Unless nobody cares for petrol at that point..