QUOTE (Rich OB @ Nov 18 2008, 07:46 PM)

Aren't HID's and Xenons the same thing? HID meaning High Intensity Discharge and the gas used is Xenon.
Yep. But you can get replacement "Xenon bulbs" that aren't HIDs, they're just regular bulbs with a little bit of xenon gas in them to give a bluish tinge. That doesn't make them any brighter though.
HIDs don't use a filament, there's an electrical current flowing through the xenon gas, and it takes a very high voltage to initially start them, then a much lesser voltage to keep them going. That's what the ballasts do that come with HID kits, a small bit of electronics to provide a very high startup current, and circuitry to stabilise that for normal operation.
Xenon-replacement bulbs as you can get in Halfords are a waste of money. A proper HID kit is miles brighter.