Actually, bi-xenons do not use 2 HID bulbs, but one with a cut off shield which is then retracted by a solenoid. Hence, there is zero warm up time for the high beams.

Litronics always block half of the beam with a permanent cutoff shield, meaning that they never use the full light output of the xenon bulb. ;)

I'm not putting down Litronics. They are still much nicer than halogens. :)

Do the 987's, later 996's and 997's have a true Bi-Xenon system? Particlewave is correct that the 986 litronics have just one xenon bulb per unit. I just thought that Porsche had updated the system.

When I was refurbishing my litronic headlights, I could not find H6W bulbs locally and ordered them from Rockauto.

I'd like to compare a set of Particlewave's bi-xenon's with my litronics. Right now, my standard of comparison is my old halogens to my retrofit litronics and I am much happier with my litronics. Maybe it is the little kid in me, but the rotation of the xenon bulb when you turn on the high beams is a nice feature.

Here's a video I shot of their operation after I installed the self-leveling system: https://www.youtube.com/watch?v=YGkfebCCf2Y

This shows the start up sequence (H6W parking lights first) self-leveling at start up, and then high beam operation. (If you look closely, you can also see the yellow light from the halogen high beam when the litronics rotate up.)

I also tried to show how the leveling system reacted to changes in the attitude of the car by jacking up one end.

Here is a thread with more information on my adventures with litronics: http://986forum.com/forums/general-discussions/55840-can-you-endure-one-more-litronic-thread-me.html