Actually there is nothing inside the C-class's door which is a problem. It's the actual inner seal itself which is abrasive. Had the felt put on and no scratches since. That and I try limiting how much I roll down the window too. That problem applies to all MB's of all shapes and size and number of doors. You have to go to a window tinting place the knows MB's really well and will install moleskin inside the door to protect the tint. Have mine on for about 1 1/2 years, no problemo. Boss just told me his tint was scratched up in 4-5 weeks on his E320 so he has to get it re-done but at least this time I warned him.