Well it all the equipment is in my sig except I am running a BXI2610 instead of the RD amp. So for how it's installed, the sub is firing up and the port is firing back. So basically the sub is firing right at the trunk lid. I am thinking about rebuilding the box and firing sub and port into the cabin to help with it, since that should take care of most of the rattle I would think since the pressure would all be getting forced into the cabin. But basically with the design right now I am fucked so some of the closed cell foam kind of lessen the impact at all? Great help. Please spend some time when you make threads to define what your goals are. Perhaps starting with the simple things even like what kind of car it is... <--doesn't have sigs turned on which is rather normal here Didn't know that you had sigs turned off. Ok here is the break down. It is a RE XXX 15 in a roughly 3.5-3.6 cube box before sub displacement. It is sub up port back running off of a BXI2610 in the trunk of a 2002 Grand Prix. My back seats do not fold down, unless I go get some 04+ grand prix backseats which I can modify the brackets and whatnot and make them fold down. All I have is a little section where the back armrest is that folds down and it is down at all times. What else do you need to know? 225 amp alt, kinetik 2400 in the rear. I just put two more layers of deadener on the trunk lid the other day. Note: This problem only seems to be happening at night when it is nice and cool compared to the days. So I wonder if it happens to do with the metal slightly changing due to temperature variations. The trunk is nice and heavy now too due to the deadener, in fact it will not even stay open once you close it slightly.