If your shocks are too "hard" then they will not allow the spring to recoil fast enough after the compression. We have found this with the race cars, running adjustable koni's. If we wind on too much rebound, the car gets"sucked" down to the ground, because the spring can not push the shock out fast enough.

This sounds kind of cool, but in reality it limits the suspension travel siginificantly, and gives a VERY hard ride, as the spring is already compressed somewhat when you hit the next bump.

What you want to do (in my oppinion) is select a spring rate that is comfortable, and then select a set of shocks which will "control" the oscillation of the springs. Any good Suspension shop should be able to help you with this. Alternatively...... go for the adjustable koni's .... I found them to be great.