Harvey Spencer wrote:

It uses the D1S bulb xenon arc bulb which is better than the D2S
commonly used in automobiles since it has the starting ballast
integrated into the base of the bulb.

RST Engineering wrote:

$500 a bulb sounds a bit like a rip-off to me.

Something's not right here.
http://www.rallylights.com/hella/HIDCapsules.asp lists the "better" D1S
bulb significantly cheaper than the D2S, and neither one approaches $500.