In HK, OEM costs around USD580 (made by Valeo with BMW logo) and Valeo costs around USD390 (without BMW logo). Labor cost is around USD200. I replaced mine 2 years ago at independent garage. If you do it at dealer, I believe it costs at least USD1,300 including parts and labor.

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--2004 E53 X5 4.8is - ECE version; right hand drive; Located in Hong Kong; ext. black sapphire metallic; int. leather black; adaptive dynamic bi-xenon headlights; 16:9 onboard monitor w/o navigation; 20" genuine BMW Y-spoke 214 wheels with Bridgestone Dueler H/P Sport tires; Int. rear view mirror w/ compass.