Originally Posted by Kento

Which ones "work quite well"? Are you referring to the HID retrofits? If so, I'd have to disagree, as I have that setup. The low beams are OK, but the high beam pattern is poor. The light bandwidth of HID doesn't lend itself well to simply moving the location of the bulb to change the reflection/location of the light pattern, and especially with a projector lamp. OEM HID lamps do not use a "bi-xenon" bulb configuration because of this.

Originally Posted by J_J

I think what you are describing is an HID kit. In a bi-xenon projector the bulb does not move at all. Instead, a shield blocking off the light above the cutoff drops down and that is how you get illumination above the cutoff line. The transition (solenoid dropping and raising the cutoff shield) happens almost instantly. In aftermarket HID kits with a high beam option, there is either a scoop that tries to emulate this effect or the bulb moves fore/aft to change the beam characteristics.

All xenon bulbs themselves are low beam only; if you switch on your high beams the HID bulbs will likely switch off.

These are the components I will try to use shown below. A lot of high-end vehicles have bi-xenon as a lighting option (probably adds about $500+ to MSRP). The projectors below are the same ones used in the new E-class Mercedes and 7-series BMW.



I'm going to try these but they are bigger than the M3 projectors I was using so this project is going to take some time.