I keep hearing about a problem with the tint in mustangs scratching when you roll the window down? what exactly is it that I should replace, and what should I replace it with

 

the weather striping on the inside of the door , some felt or moleskin as others have said...

 

well according to FORD, and I believe them. There is not an issue with the weatherstripping. Most likely dirt getting caught in there. They are replacing the tint on my passenger side because it is scratched but there are no scratches at all on the drivers side window, so I don't think it is the weatherstripping.