Coogan--If you want to run a transverse rear spring, use the tubular rear crossmember and another suicide mount on the rear crossmember.---If you do that you won't need a Panhard rod, and you should use the 4-bar set up with the urethane bushings which will allow the flexing necessary. I would run the spring in front of the rear axle, which helps offset the rearend away from the rear crossmember to avoid any interferance between the pumpkin and the rear crossmember. Since you will be making the frame yourself the truck ride height can again be tailered by how high you make the rear suicide mount.