Welcome to the forum Wurm!
Do yourself a favor, and read EVERYTHING written in the Encyclopedia. It will give you a lot of knowledge about W220, and if (WHEN!) you do experience a problem in the future, you will remember reading about it, and can go right back and find a solution.
This is a great forum, and a lot of knowledgeable guys come here every day. If you don't mind getting dirty, this forum will save you tons of money.
You have a nice ride