Just get this, everything you need and do the retro, that's what I'm doing in my black housed lights since I have to reseal them anyways. If you're going to go HID do it right or not at all. Get the clear lenses for the morimoto projectors it will have a killer cutoff.
Bi-xenon Morimoto Mini Stage III Kit (D2S) - Complete Kits from The Retrofit Source LLC