i have owned a 560sel and a 560sec from new in 12/86. both cars have been immaculately shoed and maintained for all of their mileage. the sel is a couple thousand miles from 250,000. the sec is just turning over 81,000.
both cars have always been susceptible to cross wind interference[i can't think of another word]. when i first noted it shortly after taking delivery, the service director of the dealer told me that it was systemic to the series.
when questioned, so did the zone rep for mbusa.
and most interestingly, so did some of the reviews of the series in the buff press.
i have found a susceptibilty to cross winds to be an idiosyncrasy of the series.
other posts notwithstanding.
i also own a 1979 6.9, a 1995 e320cab, and a 1997 s500c: none of these vehicles are as cross wind sensitive.