As long as you realise a panhard bar cures wallowing , NOT roll as has been suggested here.
A sway bar is for roll.
I'm going to disagree on this one. The roll center on a torque tube rear end runs at the height of the universal joint. The roll center with a Panhard bar is where a line directly up from the axle crosses a line from the center of the u-joint to the center of the Panhard bar. Basically, this is right at the height of the Panhard bar, a good 6 inches above the u-joint. The closer the roll center is the the CG, the lower the roll. 6 inches is a pretty good improvement.