Reduce Cabin Noise. By replacing your old stock lower shift boot, you will reduce the amount of road noise and road debris that enters the drivers compartment. Upgrade your Foxbody Mustang with this quality replacement SR Performance Lower Shift Boot and enjoy a quieter ride today.Exact Copy. This SR Performance Mustang Lower Shift Boot is compression molded from EPDM rubber into an exact copy of the original stock piece to ensure a perfect fit. Application. Designed for all 1979 to 1993 Manual Mustangs, this SR Performance Lower Shifter Boot installs under the exterior leather shift boot in the factory location.