Replacement Headlight Bulbs
A summary of an article in the January 2006 Consumer Reports
Tested 5 premium bulbs:
APC Plasma Ultra White
GE Nighthawk
Phillips Crystal Vision
Wagner Tru-Vue
Bulbs priced $26-40 per pair, 2 to 3 times normal replacement bulbs.
3 test vehicles used (Of 15 tests for distance in detecting a dark object using a
human subject in the car, only one bulb in one car improved low-beam sight
distance, the other 14 were the same or worse. And the one that did
performed worse than OE in another car.
Glare to oncoming drivers was no worse than OE (these were all advertised as "Street Legal per DOT".
Some drivers subjectively preferred the “whiter” light the legal premium bulbs gave.
I do use Silver Stars and don’t notice a significant difference from stock.
If you want a significant improvement, Litronics kits are available from your dealer or from Porsche Dismantelers.