philsey,
Here's a link explaining why installing a kit is a bad idea:
HID conversion info
What it boils down to is the position and orientation of the light being generated. The filament in a regular bulb is side to side and an HID is front to back. The reflector is designed for one or the other. Swapping them puts them in the wrong location and changes the beam pattern.
If you want to upgrade from a halogen to a HID system or downgrade from a HID to a halogen you need to change the reflector as well