Originally Posted by Brian-bmw

I have a document with every known good MKIV part number, to help cross-reference what you may have available to you. I will try to dig it up and post it. One of the things to look for in a MKIV is a higher SW number on the part sticker. No one knows conclusively what the difference between the SW version printed on the part sticker, but it seems that the most desired units are SW3.0 or greater.

Also, you want to make sure the units are already coded for the color navigation systems and not the "business" or monochrome systems. Most dealers have no clue how to re-code a monochrome MKIV to a color MKIV.