Well, I got some subs in my 98 bonneville se, and I cant stop the rattling in the trunk area. I don't know if its like my muffler,suspension, the spoiler, or even the plastic lining inside the trunk. I need a solution to this, or some sort of sound proofer so it doesn't sound like a million wild animals attempting to kick my trunk open.

If the sheet metal is rattling then you need to add mass to it with mats like Dynamat or Raammat or something. I have used the Raammat. Dynamat has a spray-on that is similar to rubberized undercoating but i haven't tried it.

Before you use these products be aware that they can be stinky and messy to work with, and very difficult to remove. But they do work.

i perfer using hushmat because it is easier to install than dynamat and last longer. elemental designs makes a sound deadner called e dead. It works great to. I think they even make a 60 or 80 mil. type now which means you will need to do less layers of it. I have a few pics of e dead in my sig. Check it out. It does wonders for vibration reduction