There is not a difference, Xenon is actually just one type of HID lamp. Ever see the street lights that are yellowish colored? How about the ones that have almost a green tint? Those are all HID lights. The yellowish ones are called mercury-vapor lamps, and the greenish ones are sodium-metal halide lamps. Then you have the bluish xenon lamps, first used in sports stadiums because of the fact that they closely resemble daylight, and then later adapted for automotive use.Anyone know the difference between HID and Xenon. Which is brighter?