HID bulbs can be used in projector headlights, but there are a few things to keep in mind. First, HID bulbs require a ballast to operate, so make sure your projector headlight has a built-in ballast or you'll need to purchase an aftermarket one. Second, HID bulbs produce a lot of light and can cause glare for oncoming traffic, so it's important to aim them properly. Finally, HID bulbs have a shorter lifespan than halogen bulbs, so you'll need to replace them more often.