Mercedes iPhone Dock

Confession time - I put in my order for a new 3G iPhone yesterday, so only a month or so to go before I get my hands on (please, please let the exchange synching work like a dream). Obviously, Mercedes were thinking about me when they announced this little toy yesterday - the iPhone dock. It charges your phone, hooks it into the phone system in the car, and allows you to get at your music from the hifi. Now all I have to do is work out two things - can they retrofit it to existing cars, and can the wife survive without the CD space....