Did you have the panhard bar attached to the back axle while you were letting it hang down at the shocks full extension? If so, chances are that the rod is pulling the axle to the side. It will pull the axle to the driver's side of the car as the suspension extends.
If you haven\t done this, you will need to adjust the panhard rod length with the rear suspension loaded with the car weight, so the axle on jackstands. I adjusted the panhard rod to get the outer wheel rim edges equidistant to the fender edges - having a couple of bare rims helped. You can try doing the measurement from the tires if you don't have bare rims. Probably not a disaster since the fender edges are not exactly precision data points.
I was wondering about the bright yellow on the sway bar hardware.