I'm presuming that you have H4 headlights?
If so, HIDs won't work. The halogen bulb has two filaments. One for dipped and one for main beam. Each one focused on a different part of the reflector. HIDs are a single light source that will give you essentially main beam regardless of which beam you want.
I'm not condoning this in any way, but it you are insistent on doing it, you'll need to use LEDs.