<img src="/forums/images/graemlins/rolleyes.gif" alt="" /> Here is a good way to see how it all works. Measure the length of spring, stock, with the weight of the vehicle and rider on the spring. Now insert your spacer or crank your coilover and measure the length of the spring again with the same weight on it. Make sure the suspension is properly settled in both cases. Voi'la, you will see that the spring is the same length. Same spring, same spring length, SAME SPRING RATE!!

The only thing that changes is the position of the spring in relation to the suspension, body and wheel.