I ran HID's in my civic for a while and didnt change anything, ran off factory headlight assembly. It worked fine, still put out a great amount of light on the road. Sometimes new ones are better just so they arent to bright for on-comming traffic, But I figure BMW's blind the shit out of us all with thier design ( BMW has some of the brightest HIDs out there, they blind on coming traffic ) so its no worse on our cars..LOL