I installed high and low beams on the drivers side last night and am posting pics below. The light is noticably "whiter" and a bit (10%?) brighter, though it doesn't really show in the photos. While driving at night with low beams (good weather) the low beams reach farther, though not by a whole lot. The high beams, however allow me to see into the next universe. This at first concerned me: does it dazzle oncoming drivers too much? I enlisted some help from my son (he's ALWAYS willing to drive the xFire!) and had him approach me on a flat, level piece of road while I sat stock still with no traffic in sight. The results of this little experiment was that apparently due to the design of our projectors, even the high beams "cut off" on a line about 3' high and parallel to the road surface, producing LESS of a dazzling effect than a '95 Caprice (with low beams only) I went by 5 minutes later. How cool is that?


Conclusion: SilverStar Ultras work better than the Phillips stock bulbs but the real gain seems most apparent when used for high beams.

After reading the article by Dan Stearn, I ruminated about the different filament formulas I have used over the years. 100% Tungsten provides the greatest lumens/watt. But it is very brittle and hence short-lived. When you start to add Rhenium to the mix, even 3% to 5%, you make it much more pliable and less prone to "boil-off" at temperature at the cost of some lumen output. There are some esoteric mixes that I am not familiar with but have read about and I am sure these fomulas are closely guarded trade secrets for the individual manufacturers. The reason that "halogen-filled" bulbs are in use is that the halogen gas promotes recombination of boiled-off metal back onto the filament itself, thus extending lifetime.
To finish this line, I've been using Sylvania Silverstar (blue shield) bulbs in my Tahoe for 3 years (41,000 miles) now, and haven't seen anything that compares.

I spoke to "Technical Consultant" from Orram-Sylvania a week ago, see my prior post in this thread.