clk sat nav

hello, I'm about to buy a comand Harman Becker sat nav for my clk w209 late 2004 but there are a few different models , they all look similar but I don't want to make a purchase and get it wrong, am I right in NTG2 and A209 820 83 89 ,BE 7092 ? and what connectors do I need as the price will be...