A low speed impact in a W201, might damage the impact strip. The impact strip is fairly cheap to replace. No the bumpers were not made to take huge belts like the older cars, but they can still take a low speed impact belt well enough.

My mom got hit by an '86 Deville(old woman backed up into it), at a speed around 5 mph. My mom's car was an '87 300E. It cracked the impact strip. I believe the W201 and W124 for the US, were the first Benz's to have 2.5 mph rated bumpers.