hey, the only screws that are holding the headliner in place are that of the "oh-shit-handles", the sunvisors, and the sunvisor grounds, they are all phillips head screws. if your lights don't come on in the back of the sunvisor where the mirror is, it could also be a loose ground rattling around. or if you have a sunroof, is could be a loose connection. another quite possible culprit could be a little plastic snap in part to hold wires to your center light poped out. you can always take off your front or back pillers (they pop off with a little pull), unscrew anything (sunvisor or handle) and just take a look, the screwdriver should even be in your BMW toolkit in the trunk, and should take around 10 minutes. have fun, good luck, hope it stops rattling, i hate rattles.