it s not necessary all you have to do is remove each screw and put a washer no bigger than the size of the head and torque them both one at a time these rubber washers wear out and allow the gears to misalign the motor should work again unless there is gear damage and then you have to open the sunroof all the way you must regress the rales with mob rail grease only use oem from merceds benzI would imagine. I don't know what the regular sunroof layout is, but most models that I've seen (VW, Audi) always have the panel you can remove to access the motor that drives the roof panel so you can crank it shut in case of emergencies.
If I was you, I'd first open this panel leaving the sunroof switch connected. Turn the key on, and actuate the sunroof button while watching the motor and look for excessive movement especially where you see the motor being pushed away from the gears it's supposed to be driving. If this is the case, try to torque the motor's mounting bolts. If you can't, see if you have these same rubber grommets built into the mounting bolts that the panoramic has. You probably do to minimize vibration. You could either try calling the Mercedes dealer to see about picking up new rubber mounting grommets for the sunroof motor, or just remove one of the bolts and go to your local hardware store and pick up 1/4" lock washers that'll fit on the bolts without overhang. Try putting one of these washers on every mounting bolt you can without removing the headliner, and see if that fixes your problem. It took only one washer on the one mounting bolt I could access through the sunroof control pod to fix the problem with my roof.
Once you can actually get the roof open, you'll also want to clean the tracks with alcohol or WD40 and then regrease them with a good quality synthetic axle grease.
This won't take you long, and hopefully it'll fix your problem.