Disclaimer: I am not responsible for any damage or injury that may occur. Follow this guide at your own risk.
Alrighty folks. Here's how to install a rear sway bar. This is the TRD (19mm I think) rear sway bar, but should be the same install process for all rear sway bars.
What you'll need:
14mm socket and ratchet wrench (used for the rear shock bolt/nut)
14mm wrench
15mm socket (or what your rear sway bar kit needs)
15mm wench (or what your sway bar kit needs)
torque bar
breaker bar
floor jack and stands
1. Jack up the rear and remove wheels. I didn't take pics of removing the wheels this since I think everyone knows how to do this. Just in case you don't, loosen the lug nuts in a criss-cross pattern (never circular). Jack up the rear. There's two ways to do this. You can raise the rear via the rear jack point in the middle near the rear bumper. Now, I removed this to do my center-exit exhaust, so I did method 2, which is jack up each side one at a time. Place jack stands in position. Now remove the lug nuts and wheels.


2. Remove the nut from the lower rear shock bolt. To do this, place the 14mm wrench on the bolt side (medial side) and the socket wrench on the nut side (lateral side). Remove nut.

3. Repeat on opposite side, but unthread the bolt so that it is not obstructing the way of the sway bar (you can remove it if you want, but that's unneccessary).
4. Slide the sway bar into the bolt that was left on like so:

5. On the opposite side, line up the sway bar, and thread the bolt that you unthreaded in step 3 through the sway bar.

6. Letting the sway bar "hang down", put the lower shock nuts back on, but don't tighten them.
7. Push the sway bar forward and upward to line it up the the "free" hole. Then slip the bolt provided in your kit through. To keep with the flow, slide the bolt from the medial side to the lateral side like so:

8. Repeat on opposite side.
9. Screw on the nut onto the bolt like so:

10. Repeat on opposite side
11. Tighten the nuts onto the bolts. Remember, the lower shock bolts and nuts uses 14mm wrenches and sockets. The other bolt uses what ever the size is needed, in my case, 15mm. Torque the lower shock nut, using a torque bar, to 36 ft/lbs, and the other bolt to 44 ft/lbs.
12. Put the wheels back on. Remember, put the lug nuts on in a criss-cross pattern and never in a circular pattern.
13. Lower the car.

14. Enjoy. Remember, a rear sway bar will induce oversteer, so get used to it first before you go "all out".