Being a Mercedes factory trained technician, i have two answers. The Mercedes answer is no. All of theses systems communicate with each other and will have all sorts of issues with other components. You might also have backlash from dealers / shops if you ever have problems inside the car because it will be a pain for them to weed through your stuff and find the problem. As far as i know the MB can bus has not been hacked yet, so it couldnt directly replace your stock units.
On the other hand, the enthusiast in me says yes you can. Being that the car is already filled with technology though, means that it wont be for the faint of heart to make a great install incorporating some of the cars stock features.
Bottom line, there is no simple yes or no answer to your question.