Me and another guy figured out where the raspy vibrations were coming from with the Dynomax. It's actually behind the hatch cover where the tool kit is stashed. We both applied some Dynomat type stuff (used for car audio installs) to the sheet metal and the vibration disappeared. Before that, the vibration at certain RPMs was hitting the resonant frequency of my brain!

 

well the price has gone up... $328.88. Is there a better system to be had at around $400?

 

Their cat backs on TBIRD sound horrible, but they are quiet...