would it be okay to run HID's in my stock headlight housing or do I need projector bulbs... and why?

 

Could I use a casper shield?

 

Only if you have HIDs stock. The light output characteristics are different from halogen so not even halogen projectors will work well with a conversion kit. But it would still work better than a conventional halogen reflector which have crazy glare for other drivers and do not use their light efficiently at all.

Please visit HIDPlanet because there is just so much information there.