You didn't say what car you're putting these bulbs in.
I just put a set of European lights in my 240D this weekend. They are fabulous. I put in OSRAM 60/55 watt H4 bulbs. I have experimented with bulbs on my '88 300E as well and finally settled on standard 9004 ExtraLife Sylvania bulbs. In my experimenting my opinion has come to be that the key is in the reflector and lens, not so much the bulb. The american lights are marginal at best.
I live about 20 miles from the main highway and drive alot in the darkness on the narrow, winding two lane paved road, dodging deer and escaped livestock. The European lights in the 123 car have an instrument panel adjustment for elevation. I can raise them on the two lane where there is no traffic, and lower them to normal on the highway.
Like the other person responding to your message asked, is your concern how the lights look, or how well you are able to see with the lights? If you want to see, you will gain much more light with European lights and standard Halogen bulbs. The highpower bulbs seem to add a lot of heat inside the light assembly, I believe this would cause problems in the long term.
'84 Euro 240D, 516K miles
'88 300E 5 Speed
Over 800,000 miles in