That is a great example and answers the question how do you want to buy the right item. In a BMW logo box or from the manufacture w/o the dealer mark up.
Another real world industry example 
Dana makes 90% of the carb rebuilding kits in the world. One part number is made for the last Dodge Dakota so equipped. Manufacturing costs $5.50, the part is only available thru Chrysler Parts Distr, Dealer retail $55.00+.
We could go on and on. Buy the right products for the right application and install. Technology moves forward every day.
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2005 X5 4.8IS
The
Blue ones are always FASTER....
Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green