Just wondering how common panoramic roof problems are (particularly with skipping gear drives). I the 221. I have personally experienced it. How many others?

Since the W221 S600 came standard with all options sans a wheel upgrade or iPod integration, the panoramic roof was standard. I honestly wanted it and like it, but the front motor started slipping the worm gear at less than 36k. I try to DIY most things and probably have more knowledge on Mercedes-Benz than the average driver, so I dropped the headliner on the driver side and placed a washer where the motor housing expands causing the slipping and had no issue. But of course the passenger side motor got jealous so I am going to fix that one as well. It is well known Mercedes-Benz reuses parts from other models but I was somewhat surprised when I discovered the motor was from a W203. I didn’t have to replace it, but will say if you ever hear the grinding noise, immediately have the roof lubricated with the specified grease and do not use it if it continues grinding. Yes, on a nice day you can “assist” it closed but you will wear out parts that are significantly more difficult to change. Fortunately I learned about this and did not encounter it. Mine is still at 39,903 miles. I haven’t got to enjoy it this year as I had hoped but there is always autum and spring coming up. I just have to decide between it and the Grand National!