I'm talking about height adjustable arms. That way he can even out the ride height side to side and front to rear with a 1/2" breaker bar.
As for what performance gain you'll get... that's all on you. The parts will help you achieve more consistent results. Price should be your last concern but the difference in weight jacker type and standard sticks with perches is minimal. You'll want poly bushed at the front and spherical at the back. That should keep the noise down but help with bind reduction.
Don't bother with adjustable uppers.
Go to
www.corral.net/forums and search for "granatelli problems" or "granatelli catastrophic failure" or "granatelli sucks" and you'll have plenty to read on the subject of GMS.