Michelle:

I also own a 1992 300-E . The factory USA headlight are effective as a lighted match in the dark. Go with the factory Hella German headlights orginal have Glass lenses not after market plastic.
I haven't installed mine yet I choose to add the 1995 wiper motors and the newer wiper blades to give it the full European look, not that in California I need wipers on headlights . I also am adding the vacumn headlight switch that you can manually adjust the headlight if you have a load or passengers in the car.
Most of the group just take the old USA wiper motors out replace the lower valence panel below the headlights with 260-E panels with no wiper holes paint to match plug remove and plug the wiper washer motor and your ready to go.

I have collected and printed out the information on installing these lights so if you need copies let me know.

Bob Geco
1992 300-E Sportline 40,000 orginal miles
1968 280SL restoring family car was my fahters car.
1987 Ford Mustang notchback 5.0. under 6000 miles orginal show car.
9 trophys.