I designed and built the first of the RANDOM Technology arms. [770-554-4242] We first tested the idea by cutting and altering a stocker. Found it worked, and proceeded from there.
Pinion angle adjustment is not a tuning tool, but a way to enhance the life of the u-joints, and minimize the loss of HP to the wheels. This is done by straightening the joint angles, and minimizing angle change during acceleration.
The arm is best utilized with the addition of tubular lower control arms, GOOD bushings, and in some cases, lower arm relocation brackets.
Adjustable shocks, [doubles] are a BIG plus when tuning the suspension.
FWIW, we have these arms on some FAAASSST, as in 9 sec's, F bodies.