This is what you'll need.

Window Regulator Front Left BMW E53 X5 3.0 4.4 2000-06 : eBay Motors (item 390137808045 end time Apr-30-10 09:41:47 PDT)

Not sure about BMW part number because I never wanted to replace it with an OEM. OEM's cost 3 times the price and break just the same.

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2010 Lexus RX350 still new
2003 BMW X5 3.0i w/sport package w/68K miles. (gone Thank God!)
2002 Dodge Ram 2500 4X4 cummins diesel w/198K miles, custom repo truck
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2000 Lexus GS400 w/165K miles