If you want to experiment and increase the spring rates or limit shock travel you can add additional or taller bump stops. That way they will be helping the springs resist the compression forces. It's a cheap way to feel stiffer springs with less travel. I have a collection of the suckers. I bought mine from Fat Cat Motorsports, however as long as you get quality it doesn't matter who's you use. You could even go to a wrecker if your cheap and pick up some used ones just to play around with them.

Les