Calvert split mono's hands down the best spring out there........
SS springs will sit at least 2" higher no matter which ones you purchase. The E-body won't like it because as they launch, the shackles will hit the rear valance.
With the split mono's, they are way lighter than any other spring out there, they can be ordered for raising or lowering, and you can get the rear half made short for the E-body, which is what they need, but its your car.