Just installed a Billy Boat exhaust system in my 91 NA Z. Works just fine but too much interior noise and drone even with my choice of "road" muffler. The system already has 2 resonators /pipe. I'm thinking of lining my trunk area with Damplifier Pro sound dampener sheets. Anyone out there use them and how were they on interior noise suppression?
Quieting interior noise and drone from Billy Boat System - Pittsman08:56:28 09/23/17