Nice job Lee. I was thinking a brace across the back to hold the two aft lower control arms together. The Arizona Z setup has a billet bracket that tie the two together. With all the torque your producing, those two must be trying to pulling themselves apart. A simple strap across the bottom, picking up the two bolts on either side would really box everything together.
Your pinion mount is making my brain think of way to correct an alignment issue I have with my car.
Good luck with the test drive!
Gord