damage to the shell as in metal fatiugue is possible, the reduced shock absorbtion dose mean that more shocks will be transmited to the shell and and the mounts of the subframe - FACT . How quickly , if at all and to what extent these cause metal fatuige in the shell around the mounting to the subframe = unknown.
if it shows symptons add reinforceing plates and weld.
we had massive metal fatuige problems with a mates high powerd e46 bimmer, in the end we ended up turning the multipoint rollcage into a birdcage. all the suspention, enigne, transmition and rear diff are now mounted to this. as the shell just chouldn't take it