xenons
i got some xenons in my car and they work amazingly well however i think their colour is somthing like 6500K which what gives them the advantage of more visible light which travels furthur compared to halogen bulbs, you can also get higher kelvin rating bulbs however i think they are like 35W and what ive read is that they give about 30-50 lumens per watt and dont produce much ultraviolet light. metal halides provides about 60-130 lumens per watt so in conclusion, i rekn u can use xenons however they will not work as well as a metal halides. hope that helps