You may be surprised that the answer is not extra power. The greatest gain is to be faster through the corners, not just in a straight line. Improving the suspension allows you to brake later, carry more corner speed, accelerate earlier, and reach your top speed quicker. On the street, good suspension will lead to shorter stopping distance, reduced tyre wear and a more controlled and comfortable ride under all conditions. The ride height even determines how comfortable you are standing still. Good suspension will boost your confidence! Why compromise? Springs are the basis of suspension. A spring needs to be soft enough to be comfortable, but also hard enough to prevent the suspension from bottoming out, for instance under hard braking. Linear springs are always a compromise. This can be fine for a short race on the track, where comfort can be sacrificed for performance, but on the street a wider operating range is required. On progressive springs, each coil is spaced progressively wider apart. As the spring is compressed, more of the coils will touch and no longer be an active part of the spring, resulting in a spring rate that is constantly rising. This “constant rising rate” progressively slows down the suspension travel before it reaches the end of its stroke. The spring absorbs the bumps instead of the tyre, giving a more controlled ride, with dramatically reduced tyre wear. The soft beginning of the spring is comfortable and keeps the tyre in contact with the road more. The middle part of the spring absorbs bumps and uneven surfaces of the road. The hard end controls the chassis under braking and acceleration better.