This is from a previous post about the SLS system

To answer the question, the springs are meant to carry the load (support the vehicle weight) with the engine and leveling system off. If the car sags when cold the springs need to be replaced. The leveling system is meant to "augment" the springs under load. If you need (or want) a little more beefy suspension, or if you go to normal shocks you will want to use (HD) springs for a 300SD as they are a bit more heavy duty.

Is this true? Can the springs be adjusted by adjusting the height of the torsion bar if the top coils are visibly compressed?

All these questions! i love it.

-philip