Hi all - I have a 2008 SL500 Facelift and the stereo is still in 2008 and looking a bit dated / functionality limited. I'd like to upgrade it to a new double DIN unit with bluetooth so I can play music from my iPhone, but retain all the steering wheel functions and dash displays for nav, CD, radio, phone calls etc. Has any done it? What did you change to? Does it all work still? Thanks, Jamie.