This installation guide shows ou how to install U shape roll bars to a 2001 SLK230 Kompressor. Before starting the work, please notice that the stock roll bars lean a little forward. It is a good idea to take the top down and move seats to the very front position.
Next, we have to remove those elements, from which the seat belts run through. First, use a small torx screwdriver (smaller than what I have ever seen in a Mercedes) to remove the three screws that hold the metal plate. Then use a magnetic screwdriver to open the philips screw, which is in the seatbelt hole.

Download Mercedes-Benz R170 chrome U Shape Roll Bar install