I've driven my 300E in cross winds so bad you couldn't stand up in it and found that it's one of the best cars I've ever driven in this regard. Only the BMW 7-Series was as good in my experience.
I suspect (also) that the tire pressures are incorrect. Use the maximum pressures shown on the inside fo the gas tank cover.
Other than suspension problems there is also the possibility of incorrect tires or alignment problems.
Be assured, a properly functioning 300E is superb in cross winds.