This plastic plug was fitted to sportspack MPI versions. Fitted in the rear suspension cone so that when it bottomed out it would stop the metallic clonking noise--such as running over cats eyes in the middle of the road.
Useful on any car with 13" wheels.
An alternative item was fitted to the ERA mini as once 13" wheels are fitted it created this problem. PS-early subframes had a hole where the suspension cone sits and where the bump stop would make contact so it is only of use on subframes from 1990 or ERA cars which had a flat platform area on the mound where the cone spring sits