I had purchased some DOT approved lenses which use the H4 bulbs, and the wiring harness from
Rennbay.com : Home - Rennbay - Porsche 944 ball joints, power steering, brakes, odometer gears & accessories
The bulbs that came with the lenses were the Hella H4 xenon bulbs. It made a huge difference in the lighting. I now use Nokya Arctic White Stage2 but not very pleased with them since the light output is not as great.