don't bother with the 55W conversions. The 35W HIDs will blow any halogen/silverstar away.
Make sure to keep your color temp as low as you can while still getting the "look" you want.
The higher the color temp, the more blue/purple the light output is. Also the higher the color temp the less actual visible light output generated. So 4000k will look brighter than 6000k etc etc etc
Ive primarily ran 6000k and been happy, but I'd rather have 4000k in my hella's if i were to change it. Id rather give up some of my "sweet clean barely blue tint hellas" for the more light you get out of 4000k, with a very white light.
For some reason the 6000s in my hellas looked more blue than the 6000s in my head lights, but that may have been from substaintially less use of the hellas.
