I would be very cautious in buying an X5. Ours has been great until it hit the 6 year mark and after that it has been a money pit. I do have a great mechanic at a very reasonable price which it makes it almost bearable. The X5 has a lot of common issues which you can find out on this board. Research this forum and see if you still want to buy one. In the past 8 months I've had issues almost every month. If the car has complete records, a lot of preventative maintenance done, you have a trusted mechanic done and set aside a budget of 2k/year of repairs then I would consider it. Even if you have complete records and a PPI, an issue like the tranny or valve seal issue can come up and hit you like a ton of bricks.

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03 M5
05 X5
01 RX300