Let me tell you about my experience. I was involved in the same type of accident in my 87 300 SDL. My family and I chose to keep the car, and boy was it a long two years before we got the car back on the road in the original working condition. Living in a small town didn't help, their isn't a single decent Mercedes mechanic. I had to bring the car to Atlanta.
The insurance company gave us the value for the car after we fought with them. We then bought the car back from the insurance company and were issued a slavaged title. We then took it to a body shop of our choice. My advice take it to a reputable body shop. Check their past work out if possible. Another thing you don't want to do is wait too long on getting started on the work. The longer the car sits around the more damage that will be caused, especially to the rubber components. After the body shop is done. The DMV will have to come out and inspect the vehicle. If it passes their inspection then you will be issued a clean title.
Considering that your car is a 190E which is not a rare car or very difficult to locate, I would let it go. This is my advice, the end choice is yours.