I am going to replace my headlights with HID and projectors and would like to have a little clarification. Judging by sight, it looks like the projector housings use two bulbs, one for hi and one for low. One looks projector and the other not. Which one is for low and which one is for hi? I assume HID's will work and they don't use 9007's for them both and the housing documentation will specify which ones. Please feel free to correct any misconceptions I have.