They come in both colors, altho I find the blue is a waste of money, up close it's real intense but seems to lose too much clarity at longer distances. All about personal tatse, but that's been my expereince.
As far as where to get them, I bought mine in Japan but you can get them in the US. Check ebay or look up your local rice racer shops, a lot of em have "J-spec" products on the shelf most times, you just need the high intensity bulbs. They come at higher wattage ratings than standard H4 bulbs. At the same time they draw more amps than standard, WAY more than the old stock bulbs, so you may want to upgrade your headlight wiring if it's original.
On my old truck I went with a good pair of standard 7" halogen bulbs and added a pair of
vintage fog lights that realy increased my field of vision.
