Be carefull when you buy the aftermarket CD and install kit for your CLK. The 99 model takes a different CD than the 98 did and there is a major price difference. The 99 System is a fiber optic system and I would not recomend touching these if you are not fammilure with fiber optic technology. Yes the system needs to be configure useing the HHT at your dealer. This is very simple process.