Used 2008 E320 Bluetec Question
 

I have an opportunity to buy a 2008 E320 Bluetec sedan with 130K miles on it. I would be buying from a relative so the price is very reasonable. Since I have never owned a Mercedes or a diesel, I am concerned about maintenance & costs. Is a fuel additive required on this model? Can anyone tell me about regular maintenance required for this model? Any information would be helpful. Thanks in advance.