Here is why hid bulbs need projectors.
With you're regular filament bulb, the filament glows because of the resistance to the current passing thru it. On lil string glowing so you put a reflector bowl around it, and bam, you have a pretty well aimed, directed light.
With a hid bulb, aka a xenon bulb, its gas in a tube, and the xenon gas when a certain charge goes through it, it causes a ciretain glow. Now since its gas in a tube, vs a glowing string, the light it creates is not only greater, but less defined by boundaries since its essentailly a moving gas. So when you put a reflector bowl around it, that's designed to reflect light from a fixed position filament that glows , it doesn't work, so they stick it in a smaller parabowl, and essentially "capture" this light, and focus all of it thru a lens (the projector) and aims it. Since a reflector with no projector (lens) wastes a large percentage of the light cause its bouncing it off on all kinds of angles.
This is why some states are outlawing HIDs on vehicles that don't come with em.
Hopefully that clears up all the fuss since I somewhat explained it barney style vs, flaming
Now next time you roll out and ricer boy behind you is 2 lanes over and you're still being blinded by his lights, that's essentially what the 919 may very well do with a HID since it has such a big reflector bowl style lamp. My RR has a bunch of fins and reflectors inside that focus the filament bulbs light, and suprisingly it worked VERY well with the HID too. If the 919 is a big reflector bowl like I remember, you're gonna piss a LOT of people off at light, it will be very skattered and bright.
If you do do it regardless. Please don't go over 6k, as anything higher looks absolutely ridiculous.