Questions about HID lighting systems

I've been looking at HID headlight conversion systems, but am a little confused.

THey claim the HID bulbs are three times brighter than halogen. In PA, I think the headlights are not allowed to put out any more than 55-65 watts on high beam, so do HID systems actually put out more wattage, do they just appear brighter because of the color of the light, or is it all just hype?

Like looking at halogen headlight bulbs, they all claim to be the brightest available, yet they are all rated for the same wattage on the package.

Confused.