I have a failed radio/command unit in my 2007 Mercedes 550 SL. I have the replacement unit, but don't know how to remove the old unit? What is the process, and do I need specific tooks? Thanks much for your assistance.

I would like to advise you to get your car to the dealer workshop, It's need special tools and work procedure to do for replace command unit, if the new unit which you have is it a brand new unit you cant replace it any out side workshop because need to re programme and install new software and also re coding the command, but your unit is a second hand one you can replace so it's need to remove proper way otherwise will damaged lot's of thing like plastic trims locks if you don't know the job, and don't have the right tools.

1. The amplifier is located underneath the passenger side footwell.
   Start by removing the floor matt and pulling the carpet up from the footwell.
   
2. Remove the foam board and you will see a metal plate to which the amp is attached upside down.
   
3. Use the socket wrench to remove 4 nuts that hold the plate. Pull out the board.
   
4. Replace the amp with a new one.