SPEND A FEW DOLLARS UP FRONT.
Get a Pre-purchased Inspection done at a competent BMW independent shop or by a dealer tech who is familiar with E53 X5. Have them pull all the fault and pending fault codes. This $200-500 will be the BEST money you can spend ,as it will tell you when NOT to buy a vehicle. Anyone who is selling with service records, owner history, and not trying to push off a problem car, is open to allow a second knowledgeable independent opinion to review the vehicle being sold. Third tier corner used car lots are a BIG red flag. Ask the question: "How did these idiots get the car?" Auction? Another used dealer who could not hide the problems? Insurance write off? and many other questions as these cars are 10+ years old and the used car guys find the profit of buying junk and selling high to unsuspecting novices too un-resistible.
Now back to your question: The X5 4.8is are the same as all the other models and have the same electrical, suspension, tire wear, misc part failures. The BIG difference is we get the monster motors, that when driven hard make all these little items wear out at an astonishing rapid pace. Example, rear tires 12~25K miles. If the one you find is the 3rd or 4th car in someone's garage and the mileage is low (under 60K) look for records to show the money was spent on keeping it at 100%. These things were $70K+ in 2004,5,6. People who had money and wanted a fast SAV chose the V8.
It is the third and fourth owners who brought it cheap, thinking they could purchase and drive a expensive car on the cheap are the ones to watch out for, as NO ONE did any preventive maintenance. This is the killer of high end cars. Past owners in over their financial heads and a total lack understanding of what it really takes to maintain race horses. It not just oats that bring on the big bills.....
Good luck on your search. I found a 48K one that was a one owner in a garage of 4 other BMW's. It was a small IT business owner's weekend car. Came with a few "kid marks" but well maintained with all records.
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2005 X5 4.8IS
The
Blue ones are always FASTER....
Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green