If you have the proper MB wiring loom it's a very simple process. The wiring plugs into the dome light, so there is no soldering to do. The dome light removed by gently pushing it towards the drivers side which compresses the retaining spring clip. So can then just drop it down and disconnect the existing wiring. If you open the sunroof there is a stainless steel trim on the front edge that needs to be removed. There is a row of screws fixing this in place. Then you have enough access to fit the loom. Fitting the visors and clips is very simple, just be careful when prying up the screw reveal on the clips as they be a bit flimsy. I'm sure I've missed a few steps as it's been a couple of years since I fitted mine, but it's not difficult and is unlikely to cause you any problems. The whole process will probably take less than an hour.