I'm glad to see your not neglecting the torque boxes, I'll run you through both Upper/Lower to make it easier:
Lower:
Jack the car up, placing two jack stand on the frame rails (Not too close to the TB's though). Put a small peice of wood on the jack and jack the LCA on the rear axle side, but don't raise the axle. Just slightly remove pressure from the (Spring). Take out the LCA bolt (axle side) and slowly lower the jack to remove the spring. Now remove the other LCA bolt (If the arm just sits there, leave it). Maneuver the 90* reinforcement contraption through the access hole ont he side of the frame rail. Place the single bolt in line with the LCA bolt hole, and the four bolt holes on the floor board. You may need to do some massaging or extend the single hole, as the brace might not sit perfectly in place. Put the frame side LCA bolt back in, through the brace, through the frame rail, through the control arm, and out the other side (Visual? lol). Hop inside the car and remove the lower rear seat. Get back under the car, locate, mark and drill the four holes in the floor pan. Have a friend, witht he proper sized wrench, place the plate (With the four holes) over the drilled holes, from the inside of the car. Feed the bolts through and witht he help of the friend tighten the four bolts and snug them (not too tightly). Reinstall the spring, and the other LCA bolt. Reapeat the other side.
Upper:
No is the prime time to replace the upper housing bushings which are OFTEN neglected, or forgotten about, so I suggest you try and do it now. To make it easier, remove one of the UCA (Remove only on at a time!). Place the curved plate on the floorpan of the car and mark and drill the holes. Have the same buddy place the other plate inside of the car, and feed the bolt through. You can tighten these down now if you wish, no need to just snug them. Reinstall the UCA.
TIPS:
-When reinstalling everything, snug the LCA braces, but only hand tighten the suspension pieces in place. When the job is done, jack the rear up, and place the jack stands under the rear, and rest the rear on the stands. Now is when you should torwue the suspension items down to proper spec. Before you reinstall the seat, but AFTER you torque the LCA's in place, tighten down the reinforcements. Reinstall the rear seat, and your done.
-The plates might be stainless, but I still primered mine up and painted them for good measure.
-After the job is done, find a friend or a local shop to weld the plate inside the care to the floor pan. All 4 sides do not need to be welded, nor is a beadn necessarily need. But I still suggest 2-3 full beads (you will noice one side is VERY difficult to get to [LCA], meaning you'll have to remove more interior parts, but having all four sides of the plate in NOT needed.) I painted the welds to protect them. Do this for both UCA and LCA plates inside the car.