Shocks are not what control the ride height of your car, unless you've got self-leveling ones like nivomats. They control the rate at which suspension travel is dampened. Ride height is controlled by the initial geometry of the suspension (i.e. by design) and by the springs. Shorter doesn't necessarily mean lower... shorter and stiffer can give less than longer thinner coils. The material, thickness, number of coils, and coil height all factor into how stiff a spring is and how it will sit when loaded with a certain weight (i.e. your car).
Ok, lesson over. I've got bilsteins on my '91 780, and I like very much how they ride. The monotube design is very good at dampening small movements making for a very smooth ride, and it isn't overly harsh when damping large movements but is still plenty stiff. I'm referring to the "heavy duty" series. "Harsh" is VERY subjective. It's obvious that a car lowered two inches with stiff racing shocks and 18" wheels is not going to be as comfortable going over expansion joints or frost heaves as a car at stock height with stock springs and 16" wheels with nice cushy tires. It all depends on what your butt can handle. Sorry if this didn't outright answer your question, but perhaps the information will be useful.

-Jon
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1LT Jonathan T. Belmont-- '91 Coupe 166K 'Gustaf' **FOR SALE!!!**