I just picked up a 2000 S4 and would like to upgrade to a Navigation Plus system. I was told to look at the ebay.de sites for used systems, since new ones are too expensive. The problem is that all of them listed are for the A6 model. Does anyone know of any other sources for systems? If not, are the A6 systems compatible? I was told that the trim pieces won't line up properly. If that's the case can I buy the A6 system and then buy new trim pieces to match the S4 facia? Thanks in advance.