You want some really bright white even blue/purple headlights, so why not just buy a set of ultra-super-white-blue bulbs? Think again. No bulb will put out such efficient light. The cheap blue bulbs are a waste of money and even dangerous. Why? They use a coating on the bulb to filter out the red end of the spectrum so the resulting light looks blue. A normal quartz-halogen headlight bulb puts out a lot of red/yellow light, so in order to make it look blue you must remove a lot of the total light output. Your blue bulbs make look neat, but you actually get less light, and the blue light does not reflect as well on real-world objects. Worse, these bulbs usually try to compensate by running at a higher power, so they burn hotter and will not last as long. Worst case, your stock wiring may fail, and you may melt your expensive headlamp housings!

To get the look you need to go with a real HID system. You can change from a incandescent bulb to an arc discharge. The upgrade will use less power and output more light. But this upgrade means you need new bulbs and a special ballast.

Beware of the cheap Chinese imported kits. You will know when you are buying one because it will be incredibly cheap, and probably has plug-and-play bulbs that fit standard  bulb types such as 9004, 9005, 9006, 9008, H1, H3, H4, H7, H9. These may seem like an easy fix, but they usually fail in a very short time, and replacement parts are hard to find.

Normal HID bulbs are labeled as D1S, D1R, D2S, D2R, D4S, D4. You will probably also see pseudo-Kelvin ratings for color temperature, 4000-6000 are all you need. 8000 and above are too blue, and even get into purple. They look cool, but you won't be seeing as well. For the most light output keep it in the standard 4000 (white) to 6000 (slightly blue) range. The total light output will be maximized.

Next, you want to consider your headlamp housing type. The bulbs are intended for either projector or reflector type housings, however you will want to match the HID bulb type. The Xenon bulbs put out a very small source of light, so you must shield and/or focus this to produce the best output. The Xenon bulbs are of type projector D1S, D2S, D4S, or reflector: D1R, D2R,  D4R. The S or R will depend on your intended housing: S is for projector, and R is for reflector. The R type bulb has a shield painted on to the bulb, so that stray light will be reduced when used in a reflector housing.

The number must match the ballast type you intend to use: D1, D2 or D4.  The bulbs of type D1 have a ignitors built in the bulb socket, whereas D2 use an external ignitor, that is normally built into the ballast, but sometimes external. The D4 is a newer type that is similar to D2, but the bulb is mercury-free and requires a special ballast. You will find the D4 type on Toyota and Lexus, the ballast are usually made by Denso.

The best way we can recommend for you to do a proper upgrade is to use factory equipment. What if your vehicle did not come from the factory with HID Xenon headlamp options? Then you will need to retrofit an existing HID light source (bulb, balaast, and sometimes projector unit) into your stock housing. This is not always easy, and can involve quite a bit of work. But your results will reflect the quality and reliability of a well-thought-out system. Search ebay for take-off units, the housings can be cracked or damaged, but the HID bulbs and ballast are usually intact. Be careful not to use parts from a flooded vehicle, if the bulb or ballast gets wet it may be damaged beyond repair.

We wish you luck and hope you have found this information useful. Please leave a comment and visit my about me page for more information.