Alright..... I just installed 2 12s in the trunk and spent about two hours isolating rattles and using foam padding to stretch or cushion the contact areas that were causing the rattle in the rear deck. (trunk still rattles like a **** from the outside but that's another story) Already put foam on the inside of the license plate to prevent that from sounding super ghetto.
I threw in my Bass test Cd's to isolate rattles at different frequencies and found that the covers to the rear seat belt mechanisms located under the rear deck rattle at frequencies around 60hz...... I suppose I could take the covers off but I'm wondering if there's anything else I could do. (I already took the plastic covers off the child seat hooks... they were the first thing to go). So that's what I'm left with for interior rattles.
Now as far as exterior rattles I know dnamat is the only option. Is there anything else that I can do that doesn' weigh as much that would quiet exterior rattles? Anyone else with experience getting rid of rattles in the trunk of the 5th gen without dynamat........ If dynamat's my only option I want to use as little as possible..... That stuff's heavy.

 

where exactly did you soundproof your rear shelf/inside trunk? I have 2x10" MTXs with a 500w amp, so I dont have much rattle. What kind of material do you use, where do you buy it, do you just stuff it in between the panels?