Gents -- This is a bit off-topic, but Tom's comment about a little FM transmitter is not bad.
I have a MB GPS system in my CLK500, which is fine. But I also have the same software & capability on my PDA, which I use in the 280SL or any other car I wish. A cool thing about this arrangement is that I plug a miniture FM transmitter into the PDA then tune in the Becker Europa II and the GPS software will provide excellent spoken directions through the car's speakers.