when i did mine i went a little crazy i put it everywhere from the bottom of the front window to the back glass. also the doors just behind the panels all of the roof and the package tray. i think i went thru 4 and a half boxes of dynamat. did not get a chance to drive it yet but the doors shut like a new 300c and it seems to just firm the body up quite well, im sure i added quite a bit of weight but thats how i pleaded my case to the better half for the 572 hemi lol. thx bruce