Just a few things off the top of my head...
First, the HID's draw more current than the standard lighting so you'll want to use a relay with seperate wiring (larger wires) to accomplish this. Power would be taken from the battery or fuse block and the relay would power the HID's, control of the relay coming from the headlight circuit. Two relays needed if for two ballasts or lamps (low/high).
Same for halo's, maybe not higher current draw but you could intercept the circuit controlling the drl's and use a relay then to control them too instead of the sidemarkers that'll blink when using the signals. Anyways, I do remember seeing diagrams online somewhere, if I find it I will post the link here.
Regards...
