Ok, I have been trying for a month to try to find a good cheap way to stop the damp rattles from my subs. I found a good deal on acoustic foam from a nearbye shop. (the foam with the ridges that you see in sound studios or sometimes hanging in a large room.) I think it was like 20" X 10" strips for 24 a piece. Anyway, I have seen some pretty crazy ways to stop the rattles in the trunk (including the guy who filled his car with foam) and i like this very much. I took off my rear deck and put down a layer. (its about an inch to 2 inches thick.) I had enough on there to elevate it, but the snaps behind the seats could still secure it down. Then, I completely covered the interior of my trunk with it. But when i cranked the subs when i was done, i was amazed in the difference. I have two Infinity Reference, and i cranked them up to 300 Rms each, and the rattles seamed to disappear. I'll post pics in a couple days, but for anyone looking for a cheap way to deaden the rattles, i suggest looking into this. It was much cheaper than dynamat.

what kind of store, sounds like a good idea

i got it at a local guitar store actual, im sure you can find it around. I havnt checked www.partsexpress.com but they have everything so check there and sound domain