It was done on my car (W210) by the previous owner and they went aftermarket. I have never been satisfied with the way my rain sensing wipers work (too sensitive so wipe more often than necessary). I don't know this for certain, but I have always blamed the windshield. Sensor was replaced and had no effect. If I had to replace this one I would buy the real MB glass and any good place that does this work should be able to install it properly. You can bet a dealer is going to be more expensive labor than you can find elsewhere but they should do the job right.
Since Kent mentioned it the previous owner's dealer subcontacted the windshield job on my car. As far as I know they don't do any of their own collision repair. Try to find a MB certified body shop and if the insurance company cheaps out on the glass, pay the extra for the real deal.
Done this twice. I went with a good local glass company. Told them I want OEM glass right down to replacing the MB decals. One time they even came to my garage and I can stand there and watch. A glass place does so many windshields that I d trust them over the dealer.
Two things are very important in a windshield replacement. The windshield is an integral structural component in a crash, especially a roll-over, and correct installation is essential. Second is that dealer approved replacement companies should have been trained about the intricacies of the M-B windshields. It's no guarantee but at least a glass company that works with a dealer is familiar with Mercedes-Benzes.
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