I purchased my 2006 x5 4.4i a few weeks back. I didn't think twice about getting the extended warranty. It did cost me $1600, but is good for an additional 100,000 miles. I bought mine at a Mazda dealership.

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Current Cars:
2006 X5 4.4i
1991 Porsche 911 Carrera 2
1986 BMW 325e

Past Cars:
2000 BMW M5
1998 BMW 323i Convertible
1984 Porsche 911 Targa