I am pretty sure you have to have rear climate. I have noticed that between 04 and 06 BMW's tint on the rear windows has weakened. However this year's X5 for some reason seems a bit darker than my 06 model which had everything but Premium Sound, Nav, and Comfort Seats.

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04 X3 2.5i (Retired)
04 X5 3.0i (Retired)
06 X5 3.0i (Retired)
07 X5 4.8i (Delivered 6/20/07)