HID's need time to reach their full power because its a gas arc lighting... sa halogen once nag on, full power agad.. thats why stock setting is low beam is HID on projectors while high beam remains a halogen...
its a must that the bright beam is a halogen for safety and signaling purposes, plus white light is not as visible or readily perceived by the human eye, unlike yellowish light... our eyes are designed to see better and farther with 4300K of light temperature.. anything higher than that is a waste and is not safe.
this article explains well lighting upgrades...
Daniel Stern Lighting Consultancy and Supply