Hello all, this is only my second post and do not know if i am posting this i the right place. I am wondering if anyone knows a good place to buy a pre-owned mercedes sat nav (command) unit for my 2002 w203. I have already checked ebay, but prices vary so much and i do not trust some of the sellers. I would really appreciate if someone could throw some light on this. Apologies if this has been mentioned before. Thanks.