Replacement Headlight Parts
Instead of getting a whole replacement OEM headlight assembly (around $370) if you screw up a part of the headlight, you can replace bits with BMW pieces.* The parts numbers are from a work order at the local shop, so I can't confirm they are exactly correct.**
631212356402 --* rim ($100) Edit: this part no. may not be correct. If it is not, try 63121356402.
63121358147 -- glass/Lense ($25)
63121355396 -- reflector ($95)
I'm not sure what model BMW they are off of (Edit:* I'm informed by s4grrr that the headlight bits are off an R80) and you can prolly land the parts a lot cheaper than above.* If someone knows the BMW model # or can confirm the parts nos. (I'm pretty sure they're right), shoot me a pm and I'll edit the post if necessary.