Hey those aren't actually red replacement lights in that picture. They are a mod called Demon eyes. Basically how its done from what I've seen is the headlight is pulled apart and bundles of red led's are put behind the projector lens and hooked up to a toggle switch that taps into the cars electrical system. When the HIDs are off the leds can be turned on and give it that red eye look. At night the leds are turned off and don't interfere with the HIDs at all.

This is just one of the ways to do it. But by now there's probably multiple ways out there and some are probably a whole lot easier. There was actually a performance shop out in Vegas that was selling them for awhile but their name escapes me at the moment.