Sorry for the delayed reply, I no longer get email notification on thread replies for some reason?
If you have the Symphony unit you simply do the following.
Remove instrument cluster, 2 screws.
Put GPS antenna in the little pocket under the dash above cluster, and feed the cable through to behind the stereo.
The remove the Symphony head unit and attach the wiring adapter to the existing harness.
Also attach the aerial adapter to the FM antenna.
Plug your new DVD RNS-E unit in and slide it into place.
Job Done!
If you have the Concert unit, you will need to do the following first.
Remove head unit.
Remove Climate controls.
Romove the single din cage.
Put in a Double din cage.
Then put in a new Climate control unit (or you can file the sides down to get it to fit, it is smaller at the bottom of the console)
Then do as above.
Job Done!
With Symphony it takes 15 minutes, with the Concert it takes around 1h30 mins.
You can get all the adapters and antennas from
http://shop.kufatec.de/ and you can pick up the RNS-E unit from
www.ebay.de for between 800-1100.
I got everything needed from the one guy for £650 delivered.
Hope that helps.
Guy