SSuspect, what are you running for shocks right now? Stock?
When you switch to the hotchkis springs, you'll want to have a better shock in there (i.e. Bilstiens, koni's, hals). I could go into why you wanna do this, but for simplicity's sake, I'll just stop there.
Maniac, there is nothing "wrong" with the stock spring, however, they are just not all that great for handling, etc. They usually are starting to wear out around 100-150k miles and so when people go to replace them, it's cheaper, and makes more sense from a handling performance point of view to upgrade to an aftermarket spring, like Hotchkis. And what's nice about hotchkis is that they are a COMPLETE spring package including everything you need for a pretty darn good price, and you KNOW that the springs will be true to their advertised drop (1.25" front, 1" back).