This is often overlooked, but tell your installer to make your in-car serial cable accessible. Mine was nicely placed so that it could be pulled out through where the center console meets the carpeting on the floor of my car. This is only a concern if you ever plan on doing something "interesting" with the serial cable, such as hooking up a GPS unit or some kind of remote interface.

Also tell him to be careful not to pull the wires out of the wiring loom, they are sometimes not soldered/crimped in very well.

-Tony
MkII #554