Turn your stereo down.
More seriously though the car is prone to rattles, especially after untrained people mess with the interior. I bought mine from a guy who installed after market stereo and door speakers and I spent hours working out the rattles by removing trim panels, cleaning out loose coins and screws, then applying small dabs of urethane caulk in certain places and an assortment of felt furniture pads in others. All the rattles aren't out but most of them are.
2005 4.0 MT dual exhaust GT mufflers GT suspension and wheels