I have subscribed to this thread as much out of interest than planning on this, for I have noticed this too.
In my mind using standard dampers would be possible and should create no issue, however their movement damping action would be standard rather than uprated?
Also because they would be constantly under more compression than designed, this would be additional pressure on the seals surely. Could this create a longevity problem?
Of course they must have the possibility of an owner having a permanent additional load in their car designed into them too