Xenons are illegal .. You need projectors and auto leveling to use them..
Technically all that happens when the remove them is the ballast is removed and the original wires soldered together to get a direct 12v charge and a halogen hole put in..
I just bought new ones yesterday (including new headlights - $400 installed, cheap as!) for the R34 .. Needs to be adjusted but look impressive so far...
great stuff so yes illegal but everyone has them .. the car comes standard with it so technically its not a mod