I've seen comments about the under lit headlights on the Mark I Roadster (avoiding using that C word! ) and the later models. I was able to improve the stock headlights on my car a little by adding more grounds. But I finally took a weekend off and installed HID Headlights! I installed all with, sealed power supplies, relays, etc. to make them reliable. I also left in place the three prong plugs in case I'm out driving, blow a bulb and need a quick replacement. By plugging into one of the existing three prong plugs you pickup from the light switch, high and low beams, while still leaving in place all the dash to headlight wiring just in case. In this way the headlight switch is just a very low amp switch to control the relay that turns on the HID Headlights!
I now have BRIGHT white light waaaaaaaaaay down the road!