@WojtekPOL: short answer: no problems with my C-Class.
The Distronic PLUS manage that my car is not overtaking on the right lane. I have had several times the situation that a car on the left lane slowed down my C-Class while the right lane was totally unused.
Unfortunately I have no clue what kind of assistance package you have to order to get this. Distronic PLUS is one of them.
