Z4 Roadster (E85) Xenon headlight seeing red

My driver's side Xenon headlight has reduced intensity and is casting a reddish glow. Does this just mean the bulb is going out and needs to be replaced, or will there be other components involved? This is my first time dealing with Xenons.

I have also seen prices for Xenon D2S bulbs online for anywhere from $20 to $100. Is there a preferred bulb or manufacturer to get? There is plenty of confusing info out there.

Thanks,

Yes, that is the pinkish eye of death. Just order some quality bulbs from either Philips or Sylvania and you should be fine. Remember to replace them in pair if you want them to match light color output.