Hi
Sorry for delay.
You need to retrofit the D2B phone system - there is a kit here: -
Comand Online Ltd :: Mercedes Phone/Bluetooth :: Phone System Retrofit Kits :: Phone retrofit kit for D2B based cars
(you won't get charged the EU sales tax (VAT) as you are outside EU)
There may be some pre-wiring, but just ignore it, it wont be for the MHI/UHI system, and you want MHI/UHI. It won't conflict with the CD changer, you have to just add the D2B system to the fibre opic loop - the kit above has the necessary joiner to do that.
It may be possible to add voice dialing, but normally it was only an option for cars with COMAND and I suspect the steering wheel parts may not be available for a 02 SLK.
Richard
PS, after you've added the kit, you will need a UHI phone cradle, I suggest this Bluetooth adapter which works properly in the D2B cars:
http://www.comandonline.co.uk/ViseeO...edes-Benz.html
D2B is the Audio technology in the R170 SLK ..