if you've got an E36 that has some bass to it and now your trunk is rattling,it might be the backs of the taillights. on the taillight housings there's a backing cover that comes off to reveal the bulbs. these covers vibrate like no other. so what i did to remedy this was to put some door edge molding trim( the thin chrome or black molding strip used to protect the edge of the doors) on the taillight covers so they stay in place nice and tight. on the leading edge of the covers you can cut small pieces of the molding and it just slides right on. my covers would fall off from the bass after acouple of minutes. them jammies were mad loose. now all is better but i gotta address the rattling lisence plate now