hey i just got in a set of one peice headlights, and imthinkinof going hid.
which bulbs do i use? 9004 or h4? thanks

 

H4...it should tell you which bulbs are used on the back of the housing.

 

i may be wrong but to do HID on a US car with the JDM 1piece lamps which means that if ur car is <93 then u need a wiring kit to convert your factory 9004 (i think) to the H4/9003 type connector for your kit. alternatively you could just order your kit with the ballasts wired for 9004 but with bases for H4 housings.

if your car is 93 or newer then your most likely set since the car is already a factory H4 vehicle.