Here is a nav computer buyer's guide that talks about the differences between the various computers. There are many for sale used that are mis-identified as a MKIV. Those are typically the NAVI02 and NAVI03 unites that only work with the E65/E66. Every computer correctly identified as a MKIV will work with your car.

http://www.bimmerboard.com/members/j...er%20Guide.pdf

Here is a list of valid MKIV part numbers that would all work. This list is not all inclusive, but it is a very good start.

http://www.bimmerboard.com/forums/posts/267776/

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SOLD
2000 E38 750iL Highline Edition, Upgraded with the lastest 2006 X5 Electronics
MKIV Navigation, 16:9 Display, Bluetooth, TV/Video with Backup Camera, Sirius, and Aux Input