Koni FSD shocks

What Brett suggested is true. You want to be careful increasing the spring rate on one side, especially on the front. Unbalancing the spring rate is helpful in a race car that only turns left, but not recommended to one that is required to turn both left and right.

If the difference is great enough to require a spring leaf be added to level, you should locate a spring company and explain the problem, and have them make a new set, if they will do it.