It's worth checking your headlight aim as well. If the aim is too low or too high, the light pattern will be terrible. The rain is particularly bad if the aim is too high, you won't get much illumination down on the road to help see the surface or markings.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]