Yes, for windshield and door rubber, DO NOT purchase aftermarket stuff. GET THE MB STUFF FROM THE DEALER. There are a number of "aftermarket" types both from Asia and made by supposedly "quality" European firms such as Meyle. These are significantly cheaper than the MB stuff.

The MB stuff is of far higher quality rubber, and more importantly it FITS BETTER and installs with far less hassle. You will have a better seal with the MB stuff.

Cheers,
Gerry