I found this neon kit at stereo/racing store in the mall today that lets you put these little 1" neon tubes in your headlights... I remembered the little vents or whatever they are that are in the assembly for the highbeams, and sure enough these little tubes fit right in there. No cutting, just stick them in. Took about 1 hour to install, tapped into my turn signal for power.
Mine are turquoise... I was going for that xenon look, and it looks okay. They're not as bright as I expected, but that's probably good. With just the parking lights on, my highbeams have this cool, dim blue/green glow. They have white ones as well, cost for the whole kit is about $30.
99 M2 Dakar/Blk