Philips and Hella are the best.
Ballasts wise as well.

For bulbs make sure it's Philips or Osram.

Do not but those cheap overseas Chinese, korean ones.
Heard they won't last long .
Price comes with matching quality.
SOme i heard are half defective.
Beware.

Kelvin... 4100K, 4300K, 5000K, 6000K, 8000K, 9000K, 11000K
Small K = closer to white
Larger K = more color
True that the size means brighter, but it also has increased color that blocks the true brightness.
Heard Hella brand HID kits 6000K and above output a
pink/purple HID color.
In my stance, 4300K philips are the best to
OEM cars equipped w/ HID. However no slight color hue.
6000K are prob best for slight color hint (blue edge glow)
with a white/blue output.
Larger K HID kits just are too ricey...
looks like hybrid hyper halegon bulbs.
Catz brand HID seem yellowish and not really bright when compared to Philips.

Shop around b4 u buy.
K2, B..., anything that has cheap looking ballasts beware.

Hope this helps.
I'm a fan of Philips all the way.

~ Tommy
nite_boy@hotmail.com
San Francisco:thumbup: