I think there's some confusion in terminology on the forum and that's understandable. What that other guy calls "xenons" are just Valeo projectors with a couple of holes in the bottom to accommodate the wiring of an OEM HID ballast. HIDs and xenons are synonyms and refer to the bulbs (High Intensity Discharge bulbs are filled with xenon gas, see?). I don't know if you have to pay a premium for the Valeo projectors with the holes in the bottom, but don't worry about buying the wrong one-piece OEM headlights, it can't be done...they ALL have a cut out underneath where you can put a ballast (may have to trim the surround depending upon the exact shape of your aftermarket ballast, but that'll be true even if you get the "xenons") and they all have the same internals. If you can find a set of headlights that includes the bulbs and ballasts, you might go for that, but keep in mind that VVME (eBay flashplus) sells an HID kit for like $70 shipped, so it may be cheaper to order the headlights and HIDs separately.

 

Since you asked for OEM, I am going to try and clearly explain the differences between Factory/OEM, Aftermarket, HID/ Xenon and European e-code.

Factory Audi / North America

The 1996-1999 Audi B5 A4 (pre-facelift) came with a two piece headlight assembly from the factory - OEM. HID/ xenon's were offered in late 1997 but only on the European S4, not in the U.S.

The 1999.5-2001 (facelift) came with a few changes to the exterior which included a 1 piece headlight design but with two options. The standard headlight was a dual halogen assembly while the second option was an HID/ xenon assembly.

Both headlight assembly's were made by Valeo for North American vehicles. It's important to know this because due to D.O.T. regulation all motor vehicles were required to have an amber turn signal as well as some other features. Another important factor between the two housings is that the HID/ xenon assembly came with an access hole on the bottom for the HID wiring, which was sealed by the ballast once it was mounted. The halogen housing does not have this hole.

European e-codes

Valeo also made a headlight assembly that was not offered to the U.S. market through Audi, but is considered OEM and can be purchased through various retailers. These assemblies are referred to as Valeo e-codes, where the North America headlights are just referred to as factory or OEM and this is where the confusion comes in. Here are some of the differences of the European Valeo e-code.

1) Cutoff beam

2) No amber lenses

3) Lens design (considered superior)

4) Reflector design (considered superior)

After market

After market usually refers to ebay, blacked out, or Depo headlights. With the exception of the Depo's after market headlights are not considered worth the money because of poor light output, fitment, and construction. Some have purchased after market headlights and have had good results while many others have not so it is up to you to do the research and find out what works and what does not. The best way is to ask questions of people who purchased after market headlights that you like and get their feedback. Depo headlights have proven to be a good replacement for the Valeo e-code, since they also have a clear housing, but as of now they only make a halogen housing, so if you want HID'd the housing will have to be modified. (cut opening into the bottom.

The main reason I bring this up is for a few reasons. When you go to purchase Valeo e-codes, you are only getting the housing. Bulbs, ballasts and motors, (if you have the self leveling system) are not included. When you buy factory/ OEM headlights like from ebay, or a private party you may or may not get all the parts needed for the HID's.

Another reason to differentiate between the the Valeo e-codes and the Factory/ OEM headlight is because the Valeo e-code has a clear housing, (no amber) while the Factory/ OEM housing has an amber lens. If you do not think this makes a big difference, you may have a change of heart about it once you do a CC mod, Like I did.

Also when you are looking for headlight housings, you need to take into consideration your mechanical abilities. If you feel safe with cutting up your newly purchased headlight because you found that the halogen housing was cheaper, than you should be ok, but if you prefer not to have to deal with it, or do not want to cut up your housing than the factory HID housing is for you.

Below are some pictures of the factory/ OEM HID 1 piece housing with the CC mod





Here is the first difference - This symbol indicates an HID housing





Here is the bottom of the housing with the HID ballast mounted onto it




Here is the access hole for the wiring - which is not on the 1 piece halogen housing




Depending on which HID kit you buy, you may or may not be able to mount it to the bottom of the housing. They make some that cost like $70 and then you can get some that will fit just like the OEM ones, but they cost a little more. Here is a link to just one example:

http://cgi.ebay.com/ebaymotors/AUDI-...spagenameZWDVW


Also here is a before and after of the factory HID's with and with out the CC mod,


Before:





After: