I put sumo springs on the rear of my p32 chassis.
It helped greatly to reduce body roll.
Such as going around corners or in and out of driveways, etc.
Because my springs were fatigued, the sumo springs were in constant contact with the spring pack.
Since then, I had the leaf springs re arched and an add a leaf put in. I got my ride height back and ride quality improved even more. But now the sumo springs are about 2 inches from the spring pack so engage as more of a bump stop than a load carrying device.
The folks at Hendersons (super steer) sell sumo springs and may be able to give some more insight.