My experience with the two E53 X5 diesels i had (sold both on about 200k kms) was not bad. I did some work on the rear suspension of my 2005 X5 begause it had slightly out of spec rear camber. I had the gearboxes on both serviced just as a precaution. I replaced the rear shocks (not the air springs) on my 2003 X5 in the time i had it (think it started to leak). I did repair the exhaust manifold on my 2005 just before i sold it to my son who is still driving it. Recently had one of the injector pipes that screws onto the injector starting to leak and causing a diesel smell. I thought that i might have forgotten to tighten it on refitting the manifold but found later that the same injector pipe was leaking again. On my first X5 the rear door locks would not work remotely, but the front doors did so i just left it at that. Had to replace the plastic/nylon guides on the window regulators iirc on both of the cars on the drivers door window. Cheap job if you buy off eBay. Actually, the small plastic "washer" (for lack of a better description) that actually holds the glass onto the regulator is what broke (common occurrence on these cars) This is locally available from BMW for less than R100, cannot remember the price. Fitment is not difficult. The owner of my first X5 (2003 model) did experience air spring failure, injectors problems, gearbox problems (5 speed GM box) and i think turbo problems but this was around the 300k kms mark. My advice is buy the car but try and sell it around the 180k kms mark or keep it for ever and fix stuff as they break. Very nice car and can be economical when driven with care. Go for it! Car you can get in and drive from Cape Town to Gauteng and still feel refreshed.