I've just purchased two update satnav discs for my 2008 w211 but understand that I might need my comand firmware updated too. My question is, how do I install these two discs ? Do they go in my CD slot ? Do I need to unload all my cd's first ? How do I start the process ? I 'phoned my MB dealer who is saying that the cost of updating my firmware cost £160 and could take an hour. Surely that's way over the top.