I've never visited this particular forum until now, so my reply may come a bit late.
If you want to do an HID retrofit into your current car, there are a few things to consider:
1. Do you have reflector style or projector headlights. There are 2 types of xenon bulbs that you must consider: D2S and D2R. The D2S is for cars with projectors, D2R for cars with reflector headlights. Why does this matter?? There is an integrated shield on the bulb for the beam pattern. Very important.
2. Who is the manufacturer. There are a lot of cheapo HID kits made overseas and come in these nicely packaged boxes, such as Vision, SiJ. They are junk in terms of the correct optical positioning. The important thing with a modified xenon bulb is the placement of the mounting ring/adapter. Take for example a 9006 HID retro that I currently have in my Supra. The 9006 adapter ring has to ensure that the light is focused on the proper axis, the mounting depth is correct to ensure the light is focused at the right position on the headlight assembly. Cheapo kits are made in a sloppy manner!
Now, you might ask, who makes a reputable kit? I can name some: Phoenix Microlite and
http://www.autolamps-online.com Both companies have been in the HID retrofit biz for years and have developmental experience with both Osram Sylvania and Philips. All the leading manufacturers use either Philips or Sylvania bulbs. Hella work along with Philips as well. You will find a slight edge in white-ness with Philips bulbs.
I have organized group buys 3 years ago and am quite knowledgeable with automotive lighting. For a good resource, check out
http://www.lighting.philips.com/forum/forum_6/wwwforum.cgi
Don't even THINK of buying PIAA Super white or whatever bulbs. Been there done that. I was terribly addicted to buying various bulbs over the past 3-4 years with the claims of looking like HIDs. They may look like it, but they drastically reduce the light output of your headlights. Honestly, it's like driving in the dark with those things. I finally got sick and tired of things and then did my research on HID kits. Honestly, all the money i spent on stupid bulbs already paid for an HID kit! HID kits today can be bought for about $350-600. The Phoenix Microlite kits, among the best in the HID retro biz, is about $450-500 depending where you buy from. If anyone wants a kit, let me know, I have a contact at that company.
Another thing, HID kits now come in two kinds. Ones with color temps of 4100K and 6000K. The color temp is what makes the outlook look white or purple. However, DO NOT expect your HIDs to emit various blue/purple/pink light as you see on OEM Lexus/MB/etc...the reason is due to optics. Your headlights were designed for halogen bulbs...and not xenons. They will NOT, I repeat, look identical to OEM HID headlights. You will have the same output, but not the colorful bits of light due to chromatic aberration.
Hmmm, this posting is getting darn lengthy. If anyone has questions let me know. I don't want to use up your time with my posting...
Huy