I think they are very well built machines, but as with anything high tech, they don't age well. Take a look at a laptop computer, you can buy the newest, greatest thing on the market and in 6 months it's outdated. The X5 is like a high end computer on wheels. Mechanically they are tanks, electronically they have issues that come with age and mileage.

My X5 has 148k miles on it, when all is well it runs and drives better than most brand new cars from other manufacturers. After 10 years the interior still looks new, the paint is flawless and it drives like it's on air on the expressway, engine is smooth as butter. Can't say that about many other cars.

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Current Bimmer
2004 X5 4.4i Sterling Grey Sport/Premium

Past Bimmers
1991 318I Alpine White
1995 740I Alpine White
1991 525I Schwartz
1998 323IS Scwartz
2004 330CI Cabrio Titanium Silver Metallic
1995 540I Schwartz
2000 Z4 3.0 Titanium Silver
2000 330ci Coupe Titanium Silver