Interesting read. Lets face it X5, RR, RRS, Disco, ML, Cayenne they will all have their reliability problems, so far with my frinds the X5s are fairing the worst.....
Many have had them and since moved to RR or Cayenne. Some are multiple RR owners who have had very few problems, same with Cayenne that apart from coil packs and coolant tubes the rest of the package is lasting well. Not to mention far better quality interiors.
At the end of the day you drive what you like and live with the issues or move on untill you find a car you like so much you forgive its problems. or drive a Lexus....

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03 4.4 Sport 90k/km
whats gone wrong.expansion tank,water pump, drivers window cable,hatch spring,window blinds,rear cover, caster bushes, susp level inactive, brake sensors, CV boots @45,000km!, Ft wheel bearings, AM radio, screen with dead pixels, central informer with dead lines, passenger mirror doesn't return, rear suspension has so much camber it wears out the inside of the tyre, can't change a front indicator globe, 3 faulty so far....