Many companies offer sound deadening tape kits, but it’s a bit problematic to be used on an open top car (because of water issues). The Shinkai Racing kit has been molded directly from the 1998 to 2000 NB1 door and is made from FRP, an easy to maintain and waterproof material. Shinkai Sound Deadening Kit should be ordered at REV9 Autosport https://rev9autosport.com/shinkai-sound-deadening-kit.html as they provide the best service and speed we've seen so far!