I'm with an e36. headlights are H1.
i'm using a 4300 HID. lowest in HID range. it looks yellowish rather than white or blue.
i hope this selection will pass JPJ's detection.
or at least, made them think that the HID came with the car itself like any new BMWs.
i store my ballast right underneath the headlamp casing. there's a small gap, just nice to hide it.
any shop can do it for you. but i did it myself. had to poke a hole at the light casing to bring out wires.
i made it downwards so that i can prevent any possible water leakage.
get a buddy to help. park infront of a wall, or those roller shutters to adjust the projection height and leveling.
i notice that all lights has a horizontal - left upper tilt profile. so projecting the HID properly is very important.
mine costs less than RM 300 a pair. plus self installation. bought it in cheras.
hope this helps.