That's not an easy question to answer.

I'm guessing the older car has the MKII Navcomputer, which can have one of two styles of harness connector, like the mk1 or the mk3, the gps unit is outside the nav unit I believe, and your TV module (if you have one) could cause aspect ration issues..

There are a whole heap of variables.. I'd start by reading up over at BMW MKII Navigation System - Bimmernav BMW Upgrades and then take a look at the cars setup and doing some internest searches with your discoveries.