TR2/3/3A TR4 rear leaf spring "distance piece"?

[karls59tr]

I see from the pictures in the Moss catalogue that the TR4 had distance pieces at the rear leaf springs. Were they meant to be an improvement over the "bump stops" on the TR3?
What would happen if you put these distance pieces on a TR3.....too rigid causing an even rougher ride?layful:

 

[TR3driver]

The TR4 still used the same bump stops; the high arch (aka camber) springs were meant to improve handling. Adding just the distance pieces without changing the springs would result in the rear suspension sitting on the bump stop all the time, which would be pretty harsh.

And before you ask, the TR4 springs won't fit a TR3.