The springs can be adjusted to correct for the proper height of the car body.

The components look like this:

I believe the following are the correct part numbers (check your MY in PET):

Rear
92833351302 - adjusting nut
92833351105 - threaded sleeve
92833352102 - spring support

Front
92834353502 - nut
92834353700 - threaded ring
92834352503 - spring support
92833355100 - supporting cover

This is the 928.335.513.02

and this is the 928.335.513.01 (this one is for use up to 1986)