Sorry for the delay
Valid COMAND part numbers for W203 can be found here: -
W169 A, W245 B, W203 C, W209 CLK Facelift COMAND-APS and Audio Part numbers
The newer the better !
You will also need a GPS antenna & a map disk. Latest map version is V11 2009/2010
There is a 'integrated phone retrofit kit' available here for £450 -
Comand Online Ltd :: Phone Retrofit Kits (MOST/D2B) :: Phone retrofit kit for MOST based cars
That will work properly with your COMAND system and steering wheel controls etc.
you will also need a phone cradle such as this bluetooth device
Comand Online Ltd :: Phone Cradles & Adapters :: ViseeO MB-2 (formerly MBU2000) UHI Bluetooth for Mercedes Benz
Talk to
sales@comandeurope.com - they supply/fit for a fair price for installing all/any of that.
Thanks
Richard