Can anyone recommend any fog lights that match the OEM xenon headlights? I know they're H7 bulbs. The 2 cheap sets of bulbs I bought were not even close. Links to the products would be great. Thanks!

I'm very interested in this as well. Having the xenons and the fogs both on looks goofy in stock form.

you mean which temp ?
stock HID is 4300K so if you want to match the fogs you should get this temp

Seems like I recall a company named Hoen (hoen-usa.com) that sells replacement bulbs in the proper color temp. I've never ordered from them, but I remember the name from banner ads.

Some good info here, but can anyone verify a particular set that looks proper and doesnt throw any codes?

Just use the Phillips H7 diamond vision gloves. They're 5000K and are normal globes (non led) so they won't throw any codes or errors. They're also a quality brand so they last a long time compared to the cheaper made ones..
I've got these in my car and they look really good with the xenon headlights

After reading about this for a few days, I'm still a little confused.

I have a 2004 CLK500 with factory xenon projectors. Based on the year, I believe my lower fog lights are 9006 style. OK.. no problem.

Now on the inner two headlights, there seem to be two different bulbs in there of different size. I see H7 listed as the replacement for one, but cant find info on the other.

I am guessing either 5k or 6k temp would be a reasonable match for the factory xenons, but I want to do the other 6 bulbs at once to keep color consistant.

Do people use 35w or 55w ballasts?

Arrgh.

Can't always go by color temp on some products. I bought cheap $10 7000K bulbs and they were still yellowish. Obviously you get what you pay for so I'm looking for products other people have.

Has anyone used Hoen bulbs?
http://www.hoen-usa.com/fog.htm

Pirrone, is this what you have?
http://www.ebay.com/itm/120968889075

After reading reviews and mostly a bunch of forums of all make and models, most of the people say good things about the Hoen bulbs. Just bought a set. ($29.99 + $8.95 S&H) I'll let you guys know how it looks after I install them.

I assume that replacing any of the halogen lamps (low beam and fog lamps) with a HID bulb will require a ballast of some kind? Is there a pair of ballasts that will drive multiple sets of bulbs?

Lex, yes, true HID bulbs will require a ballast. I don't know a bout automotive applications, but ballasts can run multiple bulbs - the fluorescent fixture in most commercial office building run four bulbs on one ballast. However, in this case, many people are still using incandescent bulbs, just with coatings that mimic the proper color of OEM HID bulbs. That's what Hoen sells. If you do decide to replace incandescent bulbs with true HIDs, you'll also need proper resistors to wire in parallel to "fool" the SAM or else you'll get bulb errors messages and possibility flickering.