Mods /admins you may want to sticky this...
I found an online parts catalogue at RealOEM.com for all BMW models current and past. It features diagrams, part #s, and other information that may prove helpful. You can search by VIN or enter model info manually. You can also [with manual entry anyway] select usa or europe model so you can find info and part #s for some of the sweet euro options we don't get over here.
Here's the link http://www.realoem.com/bmw/select.do...&trans=&arch=1
Hope this helps some folks. Personally I use these things all the time working on my truck they can be very helpful showing how one part fits relative to another as well as for retrofits and "factory upgrades".