I did a retrofit with some supposedly cheap projectors/ballasts from China. The bulbs are proprietary I guess I have not seen them for sale separately, but the projectors with bulbs are about $60 so really who cares. Very pleasantly surprised by the quality, they are 4300K and look about that, a nice white light just hinting at blue, although I prefer light getting into the more yellow territory myself. The high beams are incredible.
If I had to do anything different I would have gone with orange or maybe blue halos instead of white. Here's what they look like, the entire kit was $140-ish very happy with how it turned out.