I just installed some 55/100W H4 Xenon lights in my headlamps. THESE THINGS ARE GREAT! I replaced a set of 80/130 tungsten quartz halogen capsules with these, and actually looks like I can see further. How lower wattage lights work better I have no idea, but I can see better. The lights were from a guy in Group Z SoCal, and they're $40 a pair. If you already have H4's in your car, try these things!!! His e-mail address is: "[email protected]"