The weight of the car, gear ratio, tires (slicks or drag radials), auto or standard...it all factors in. Too stiff of a spring rate won't plant the tires hard enough for optimum traction and too soft causes issues. I haven't had my wagon to the track yet but i'm leaving the stock springs in it for now to see how they work. My sedan that I was racing before had stock springs with 1 or 2 leafs removed. Whoever set the car up knew what they were doing because that hooked like crazy. The springs were soft enough to plant the tires very well. I have some video on You tube and you can see how well the tires planted. Not knowing your setup it's hard to say exactly what might work for ya.