Fog lights and driving lights are very different lights for different purposes. By saying "fog/driving lights" you're lumping different lights together like they do the same thing. Kind of like saying headlights and tail lights are interchangeable.

A true fog light is supposed to light up the ground immediately in front of the vehicle under the fog. By keeping the light low it prevents the light from reflecting back at the driver. Fog lights are not designed to be used as primary headlights at any speed, especially high speed. In foggy conditions I will turn off my headlights and drive with just my fog lights but only at greatly reduced speed. If the weather is bad enough that my headlights are reflecting back then it's bad enough that speed needs to be reduced anyway.

A driving light is a much longer, narrower beam for lighting up a long way down the road. Use of driving lights is illegal on most public roads.

 

I never said they were legal, just a brighter / clearer alternative to stock on high beam, clearer but same as stock on low beam.
Several of us are using them here locally and have had no problems with them or the electrical system.
Bottom line for me is ....I like to see @ night.....with all the deer in the roads here we need all the help we can get, these bulbs provide the best of both worlds great vision on high, not offensive on low, descent price and obviously easily converted back to stock.

 

No, I'm grouping them as auxillary lights mounted on the front that most people I see on the road using them haven't a clue how to use or aim properly.
That's a far cry from saying headlights and tail lights are interchangeable.

As far as driving lights being illegal on most roads, I've lived in quite a few states and they weren't illegal. There were, however, regulations on how they could be wired, generally being that they could only operate when your high beams are on.

Back to he OP, here's some information people fail to consider. But advertising is a powerful force that people are conditioned to believe without question.
http://www.danielsternlighting.com/t...s/Hid/HID.html

 

Oh, look: my hobby horse. :-)

One point I haven't seen anyone mention here -- and one of my deciding factors for buying an 02 or earlier Series II -- was that those projector headlights give me hives as well... but my reasons are a touch different.

Anyone remember the old, old Volvo bricks, with the 8x10 headlights? Ever notice that those things don't blind you much at all?

There's a reason for that.

If you're going to push a specified number of lumens out the front of a lamp, the size of the lamp lens determines the apparent brightness of the lamp -- we don't really integrate against the size, so a lamp 8 times as large will appear 1/8 as bright, even though it's throwing out the same amount of light.

I'm talking about when you're looking at it mostly off-axis, of course, as we generally are with other people's headlights.

So, if you pick a car with the largest possible headlight lens, you're contributing to gratuitously pissing off the smallest number of drivers. :-)