Advantages for HID Lights :

HID lights generate a greater output of light compared to the original halogen
bulbs, which can up to 3 times. And its light covers almost 70% of the road,
so it's good for road safely as driver has a better vision on the road. If you
have the experience in using the original halogen bulbs, the bulb life is always
short, but HID lights can last up to 4-10 years with a greater durability, can
withstand a greater amount of vibrations and shocks. HID light is a good choice
when you are planning to upgrade your car headlight system, as it provides greater
light with lesser power consumption, can save it up to 25%.

Color Temperature:

HID Color temperature refers to the degrees (K) , which simply the measures
of the color for the lighting output, like golden yellow, white, crystal white,
blue …

Degree (k) refers only to the color, while lumen refers to the lighting intensity.
So the higher the color temperature (degrees K) doesn’t mean a higher light
intensity (lumen). Here is the summary for the common color temperature on the
market --

3000K (Golden Yellow) , 4300K (Bright White), 5000K (white), 6000K (Crystal
White),8000K (Crystal Blue), 10000K (Aqua Blue), 12000K (Purple-Blue).

Bulb Size :

The common bulb size is H1, H3, H4, H7, h13, 9004, 9005, 9006, 9007, D1S, D2S.
And it has single beam conversion, hi lo kits, Telescope and Bixenon kits.

Here is the summary for the features and bulb sizes ranges
for all those kits.

Single Beam Conversion Kits -- H1, H3, H4-1, H7, 9004-1, 9005, 9006, 9007-1,
with 2 ballasts and installation clamps.

Hi-lo Beam : H4-2, 9004-2. 9007-2 hid for low beam and halogen bulb for high
beam, with 2 ballasts and installation clamps.

Telescope Kit : H4-3, 9004-3, 9007-3, single HID can switch between high beam
and low beam, with 2 ballasts and installation clamps.

Bi-xenon Kit : H4-4, 9004-4, 9007-4, 2 HID bulbs on each bulb, which works for
high and low beam, with 4 ballasts and installation clamps.