I used the Blue Vision before. It is totally legal, don't have to worry about the "illegal" issue. btw, Blue Vision is not "Blue" at all when you light it on. It is a little bit "whitter" than the stock yellow blub you've got. I think you've got a very good visibility of that light, the light output is good on the road. And I turned to the Diamond Vision after a few months, and then I start worrying about the "Blue". Coz you can see a obvious Blue light on the road. And I lost visibility as well ... Not as bright as the Blue Vision and the stock blub. This prove the higher the K, the less on light output. The higher K only means the blue they are (from yellow ==> white ==> blue ==> purple) Anyway, I just changed to HID on last week. I think I will never go back to halogen bulb again. Save more money in long term, coz I don't have to worry about the short life spin of halogen Blub and paying another $60 - 100 for a pair of bulb