both my mechanic and BMW sales guy said to me that if I\m in a market for a 4x4 bmw to by E83 as it is the most reliable BMW from late models. It has very cheap suspension and parts are tried and tested.
Later I read a review on it which listed all the issues and in the end said the car is super reliable for its age, price etc.
Problem areas as others too said>
- blocked drains means water in car, check carpets to be dry!
- failing springs *esp on cars used on poor roads
- gearbox software glitch which means bad uphill performance
- turbos that fail on diesels
- water gets to headlight washer motors
In Europe, a 2l diesel with manual is considered the best and most reliable car to buy from BMWs I\ve seen in most magazines.