[Techno Duck]

While sand blasted sealed beam lenses that are years old are not doing anything for lighting the big improvement will come from upgrading the wiring. If you measure the voltage drop at the headlight plug i bet is somewhere around 12v which well under your charging voltage which is probably around 13.5-14v. This ~1.5v may not seem like much but if you can find a chart that compares light output vs voltage the relationship is not linear.. so the more voltage drop you get your lights get exponentially dimmer. At 12v you are selling like a 30% reduction in light output approximately.

My XJ Cherokee sufferered the same headlight wiring problems as the 944, all the voltage runs through the switch and the wiring is pretty pathetic. I actually installed the Rennbay harness on my Jeep and the light output was probably 2x better. Voltage at the plug with the original wiring i measured at barely over 11v. With the new wiring i had the same voltage as the alternator output.

I am also using the e-code lenses which have a far superior beam pattern, for a while i ran 90/100w bulbs but they burned out pretty quickly.. usually only got about 3-4 months out of them. This was using quality Osram and Philips/Narva bulbs ($$). I went back to standard wattage bulbs with the e-codes and i think its plenty adequate.

Basically what i am saying is if you want the best improvement over what you have right now, upgrade the wiring first. New lenses will help, but the wiring is your real bottleneck.