I installed 7500K Halo bulbs in my '08 550 in 2010. I just had one burn out and went to replace it. When i removed the bulbs I noticed that the insulation had burned off the wires at the plug. Just an FYI for those people running different bulbs from stock. I went back to regular bulbs and repaired the insulation. I forgot to take a picture.

 

My '08 had the same thing before I changed the bulbs. If you live in a hot climate, it's pretty normal for the rubber insulation to dry and break off near the connector. A little electrical tape over it, job done. It's not from the high temp bulbs, just standard BMW attention to detail (lack thereof).

 

I recoated my wires with high temp liquid insulation. I will see how long that holds up. So another similar wiring issue to the rear tail light wiring.