There’s a ton of stuff on eBay that you can slam into your car and one of the best sellers out there are HID Xenon upgrades for earlier model cars, or for cars that did not originally come with Xenon style lighting.  These kits are actually pretty cool and very effective when properly used, and an absolute disaster when not applied properly.  So, before anyone gets crazy and starts clicking away on eBay, we need to make sure that you can actually benefit from one of these kits, and it’s all about the light housing and how your car was set up.  There are basically two types of light housings, and how they distribute light from the bulb.

e46 headlights

Above is an exposed view of a BMW 3-series headlight, I chose this headlight assembly as it has both styles of light distribution in one assembly.  To the left is what we call a reflector style housing and it’s quite obvious why.  To the right you see the lens style housing, quite a difference.

Lens style housings employ a glass lens to direct light from the light source to the front of the car. These housings always have a thick glass lens that resembles something you’d see in a telescope.  There are reflectors behind the lens that direct all of the bulb’s light to the lens and it projects it forward with a distinct and intentional pattern.  So whether you have a standard halogen bulb behind the lens or a Xenon bulb, all of that light gets directed to the lens before it exits the housing. Basically, you can put a candle behind the lens, or you can put a basketball court bulb behind it, it doesn’t care as the lens does the work. Here’s an example of what the light pattern should look like against your garage door.


Reflector style housings are all based around the bulb and its output.  They reflect and direct the bulb’s light forward based on fancy engineering and modeling.  Change the bulb, or the output for that matter, and the reflector will no longer operate as it was designed. This is extremely important when it comes to the HID kit you were about to order 5 minutes ago.  Don’t buy it.  It will not work and it is actually illegal according to the Department of Transportation. Once you have an HID bulb in a reflector style housing, the reflector is basically useless and the light goes in every direction without regulation.  You won’t see better, and you’ll blind on-coming traffic.  Here’s a mis-guided fellow who thinks he’s done something good, when in fact he’s pissing everyone off that he passes.

Now that we’ve established who can and cannot use an HID upgrade, let’s talk about the kits themselves. They come in 35 watt and 55 watt.  Get the 35 watt kit for normal use, bigger isn’t better so don’t get hung up on this.  The kits also come in many different color temperatures that are typically rated according to the kelvin scale. I would recommend that you get somewhere around the 4500 range.  The chart below shows the differences, but in real life, anything above about 5000k will look blue.

As far as vendors go, I’ve had great experiences with DDM Tuning as they are local to us and have great customer service. These are great kits, very reasonable in price, and deliver incredible results.

Light ’em if you got ’em . . .

Chris Keefer

Independent Motorcars

5836 Autoport Mall

San Diego CA 92121