DON'T WASTE YOUR MONEY BUYING DYNAMAT! It's not the issue.... I had the same problem and looked at the deck lid to see where it was vibrating (basically where the paint was coming off). I went to lowes and bought single side stick 1/4" weather seal and put it along the curved edge of my trunk lid and it solved the vibrating problem. Sure, dynamat will help a lot with vibrations and for better sound but if you just want to get rid of the vibration then get the weather stripping from lowes/home depot. EASY fix!
If you guys need pictures let me know!