Hot Rod Roy---I believe you are incorrect. A car with a suicide perch on a transverse leaf spring is no different from a geometry point of view than a car with a transverse leaf spring mounted under the front crossmember. Both will suffer equaly from "shackle rock" where the weight of the car has a tendency to swing back and forth on the spring shackles. Both systems will benefit equally from a Panhard rod, or from a dead perch spring mount.