I have 2 Euro Beam 4000's, and 2 Pencil Beam 4000's on my roof rack. The Euros are on the outside and the pencils are on the middle.
The "Euro" beam lights are different than the US sold "driving" light in the respect that the Euro lights have a small 5 watt bulb IN ADDITION to the larger normal bulb. Over here in Europe, you can ride around, day or night with the small bulbs on, it has more to do with city driving and saftey than anything, but all of the big rigs here in Germany run the 4000's up high on the roof racks and it looks cool with the low watt bulbs glowing in the night.
I have converted all of my auxillary lights to HID, (4) Hella 4000's on the roof rack (no glare at all), and two Hella 700FF driving lights on my bumper. This is the BEST thing I have done to my lighting system by far.
Here is the small 5 watt "euro" light only, lit up. (look closely at the outer two, you can see the dim glow)
Here is the entire rack lit up, after switching to HID. This is broad daylight around noon.
Here are some pics showing the night effect, before aiming.
Normal headlights, taken from inside the truck:
Truck High Beams, and all 4 Hella 4000s on, from inside truck.
And the last two that I took yesterday showing the 700FF's on the bumper also.
If I had to change anything, I would have gotten (4) Euro Beam patterns for the roof rack instead of the pencil beam/Euro beam. The Pencil beams are just too powerful and narrow for anything I do. They project well over a mile in a straight line, but there arent many straight roads/runs where I live. I really like the side light that the Euros put out also.
Whatever you decide to do, I highly recommend the HID conversions.
~James