XRAY - Model racing cars

Maybe this helps (coming from the T2 setup book):

Stiffer springs
Makes the car more responsive.
Car reacts faster to steering inputs.
Stiff springs are suited for tight, high-traction tracks that aren’t too bumpy.
Usually when you stiffen all of the springs, you lose a small amount of steering, and reduce chassis roll.

Softer springs
Makes the car feel as if it has a little more traction in low grip conditions.
Better for bumpy and very large and open tracks.
Springs that are too soft make the car feel sluggish and slow, allowing more chassis roll.

Stiffer front springs
Increases mid-corner and corner-exit understeer.
Increases steering under braking.
Increases the car’s responsiveness, but makes it more “nervous”.

Softer front springs
Makes the car have more steering, especially mid-corner and at corner exit.
Front springs that are too soft can make the car understeer under braking.

Stiffer rear springs
Makes the car have less rear traction, but more steering mid-corner and at corner exit. This is especially apparent in long, high-speed corners.

Softer rear springs
Makes the car have more rear side traction mid-corner, through bumpy sections, and while accelerating (forward traction).