Okay, I have two 15' soundstream subwoofers http://www.lesscoelectronics.com/v/v...%20T515-2T.jpg
There about 2,000 watts put together, and they hit very hard. Inside it sounds just fine but outside of the car it's a lot of rattling and shaking. So i was wondering what i can do to reduce the rattling.

 

lots of sound deadening. common rattle sources are the trunk latch, license plate, rear bumper, and tail lights. placing closed cell weatherstripping foam behind the license plate and tail lights will help. wrapping the trunk latch with electrical tape can help. foam/rubber where the bumper meets can help.

and lots of sound deadening.