Quiet door operation doesn't just come from proper striker adjustment or new door-perimeter weatherstripping. It also comes from having window glass that doesn't rattle-easily done with new window channels and weatherstrips. They also make for smooth operation when it's time to roll the window up and down. This is an easy fix you can accomplish in an afternoon.
Mustangs Plus offers a complete window channel and weatherstrip kit designed for easy installation. We also ordered new Scott Drake window stops. | 
The weatherstrip clips can only be used once. After they're installed, they can't be removed without damage, so take extra care. | 
First, remove the door handle and armrest. |
Next, Dave Kunz removes the door panel and water shield from his '68 Bullitt replica. This Highland Green fastback has appeared in Mustang Monthly and other publications throughout the years. Ford honored Dave by including his replica in its '01 Bullitt GT advertising and promotion efforts. | 
The paper water shield comes off next, if your car still has one. These are frequently missing. | 
When Dave removed the rubber window stop from the bottom of the door, it fell apart. Los Angeles is especially hard on soft parts due to air pollution and ozone levels. |
With the rubber stop removed, Dave cranks the window deep into the door, making it easy to remove the weatherstrip. Remove the door-end screw first, then carefully remove the strip. Be careful not to damage the paint. |  | 
The inner felt strip is removed next. Very gently work the strip, but don't worry if the clips are damaged during removal, as they won't be reused. |