After purchasing my 06 X3 i began to notice a slight rattle coming from the sunroof area every so often. While this could most likely be fixed by the dealer, i decided to try myself. I noticed there were two areas near the back of the window assembly that was clearly showing friction wear from metal-on-metal contact. I went to a local hardware store an purchased some adhesive velcro strips and stuck a small piece of the soft side on those areas. The problem immediately went away. See pics below...

hxxp://img197.imageshack.us/img197/3860/img0088joa.jpg

hxxp://img188.imageshack.us/img188/2051/img0089e.jpg

Never thought I would give a care about a rattle that someone was hearing in their car.
But now that you mention it I have a rattle in my X3 too.
Thanks for giving me a place to look.

I have a rattle in my X3 too.

Just a rattle? Man your lucky! :stickoutt