I ranted on another posting that I've been more than unsatisfied with Stevens Creek BMW, Santa Clara, CA, service. I had my 2001 M3 in for various issues and one was an intermittent headlight. I've got the xenons. I'd been reading all over the web that many other owners had the same issue. My particulars were that it seemed to be temperature related, the colder it was, the worse it was. My driver side headlight would go out after going over a good bump (don't get me started about the lousy roads here in the Bay Area!). But, it usually came back to life if I simply turned off the lights and then turned them back on. But it had gotten worse over time. So, the dealer mechanic looks at my car and says that it's due to the fact that I lowered it. He actually had me drive back to the dealership so he could point out the level sensor arm (near the control arm?) was broken. The funny thing was, the other mechanics gathered around and laughed at him! I calmly explained that I agreed with the other mechanics, besides, I'd had the car lowered for about 6 years, so that didn't hold up to logic. Needless to say, it didn't get fixed and I paid for an hours labor for nothing. But, the good part is that I torn apart the headlight and found that the connector (under the rubber boot/umbrella) to the xenon bulb was actually disconnected. You'd never know this unless you peel back the boot to check. I had to clean (file) off the corrosion from it sparking. But once I blew out the assembly with compressed air and put everything right, its worked fine ever since.