This all depends on your budget. My advise is to skip the 2.0d and rather get a 3.0d. Maintenance would be similar but the 3.0d is sooooo much better to drive given the extra weight of the X3 compared to a normal 3 series. Consumption would be very similar too - in fact, on the highway, I would expect the 3.0d to be more frugal, especially if the car is loaded.
Also, avoid a vehicle if it was in an accident. Take your time to find a car - there seems to be lots of old X3s on the market.
Just my R0.02 on this too :thumb: