It depends. Stiffening up the shock will help, but then the springs won't be moving at all. You want a set up to where both the springs and the shocks will work together.
Remember though, if you go over the same bump at the same speed with the stiffer springs and struts it will jerk the hell out of the car upward. That travel the wheels take softens up the ride, so the less travel there is the stiffer and stiffer it will be. Believe me, i have pretty stiff coilovers in my car, at least for street use.