Every time a new OS version came out, the MKIV got a new part number. As far as I know, they are all the same, once you update to the latest OS.

__________________
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

Are you kidding? Can anyone else confirm? Now that's just a mess.

Some older units (I have no idea which) I believe were prone to overheating. Their on board fans crapped out, the unit would run hot and the nav would crash or lock up. I know for a fact that some units used in the 2005 model year had this problem. Personally if I were you I'd get the newest one you can find as it's likely to have less wear and tear if it's used.

It actually makes buying a nav computer much easier. If you look on the bottom area of the part number label, you will see the hardware and software versions of the MKIV in the format "HW: 1.01 / SW: x.x". The part number of the MKIV is tied to the original OS loaded on the computer, as indicated by the SW number. Almost every one I have ever seen has HW 1.01, so I do not think that there were different versions of the HW more prone to issues.

Here are a couple posts with known good MKIV part numbers. If you buy a MKIV from this part number list, you will be fine. They are all equal. Just make sure that you do not get a mis-identified NAVI02 or NAVI03 from a new body style 7 Series.

http://www.bimmerboard.com/forums/posts/217370
http://www.bimmerboard.com/forums/posts/445620/
http://www.bimmerboard.com/forums/posts/267776/
http://www.bimmerboard.com/members/j...er%20Guide.pdf

__________________
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