The new window "bristle rail" which is on each side of the door windows, is DEFECTIVE when ordered from Mercedes. Apparently the current "bristle rail" which has been recently re-produced and supplied to Mercedes as original equipment, is clearly defective for several reasons. First it is too wide, causing the window to be difficult to move, next the folded metal attachment strip on its bottom edge is poorly secured and comes loose, next the glue used to bond the fabric covering stays wet and oozes out onto the glass, making a big black sticky mess, the rail itself deforms during installation because the material inside is too soft. If you are successful and get it installed (a lot of work) the black adhesive oozes out onto the glass and sticks. When you attempt to roll the glass up, the bristle rail starts coming apart and only gets worse. After three failed attempts we called The Classic Center. They are aware of the problem and are working on it. This stuff is expensive and its a lot of work to install. Just thought I would try to save some frustration for the rest of you. Hopefully the issue at Mercedes is resolved soon. This is very unusual because anything supplied from Mercedes is usually the best. Just a temporary issue I am sure. They refunded without a hesitation.
In the meantime I found some aftermarket "Made in Germany" which looks and works great. It was much less expensive also.