I could see why if you had a stiff spring and not enough dampening this could result in some nasty behavior.
What happens if it is the other way around?
If your spring are not stiff enough for your shock (in a coil-over setup for example) what kind of behavior would the car exhibit?
Thanks.

 

Depends on the part that's overdamped. Generally-

Too much compression damping, and the car will behave as if it were too stiffly sprung - bouncy, never really settling into a corner, and having trouble maintaining grip on uneven surfaces.

Too much rebound damping, and the suspension can "pack down". This is where it keeps compressing with successive bumps and turns, not having the chance to return to normal ride height. To some extent, this is desired in autocross, as the whole car hunkers down to a lower CG. However, with an S2000, too much rear rebound damping coupled with not enough front swaybar can cause the dreaded inside rear wheelspin problem.

Everything is a compromise. Things get more complicated when you get into low- and high-speed compression adjustable shocks and still have gas pressures and rebound to play with. That's why it's a good idea to buy a matched spring/shock pair, or even better, have a shock builder that knows what they're doing.