Stiffer rear springs?

[ShadowFromHell]

My NY desperately needs stiffer rear springs. Im planning on 2gen struts/springs for the front. 10 years ago I would have just went to the JY and got some tona springs... but thats not gonna happen now. Has anyone found a spring that works? Not afraid of modifying the car/spring to make it fit.

[HSKR]

I've got a set of springs from a '92 Daytona IROC and a '91 Spirit R/T if you want.

[ShadowFromHell]

Those would help but I would like to go even stiffer. Maybe something from a van or rwd car? Jeep Cherokee front springs cut down?