I just finaly installed my R's and they pound so hard I am so happy and inside the car it sounds absolutely Great but outside my car sounds like a rattle box because my trunk is flexing like crazy when I turn it up about half way even though I cant hear it in the car.
What should I do to stop my trunk felxing? I have a 98 malibu "no spoiler"
i wouldnt get dynamat, a little too expensive. for your trunk get some edead v1se (goes for about($26 shipped on ebay for 10 sqft) or get some second skin damplifier. both are less expensive and just as durable as dynamat.
using these will reduce the rattle by alot.
if you really want to stop the rattle get the edead v3, paint it on where ever it needs to be, and then put the edead v1se over it. or vis-vera