The problem with the factory F-body suspensions, regardless if it's a Camaro or Firebird, are lack of positive caster that can be achieve through alignment adjustment, and poor camber gain curve in compression. The latter is compounded if the vehicle has been lowered from stock height (as many are).
The Guldstrand mod does two things, each having their own benefit.
1. Moves the upper control arm rearward 2. Lowers the upper control arm mounting
Moving the control arm rearward increases static caster. This improves straight line stability, return to center steering wheel feel, and increases tire lean as steering angle increases when cornering.
Moving the upper control arm down is changing the pivot point of the control arm and increases negative camber gain.
Many aftermarket upper tubular arms have some added built in caster but can still benefit from more. Whether the Guldstrand mod is compatible may depend on how much total it adds, and/or what is the clearance from the arm to the frame brackets. Also, moving the upper ball joint rearward will reduce clearance between the front tire and the rear fender (especially at the fender bolt). You can gain a little more room by changing the fender bolt to a button head, or remove it altogether. I have a version of the Guldstrand mod with my DSE uppers.
The Gulstrand mod will not change ride height.
Tubular control arms may have added built in caster, but unless they are running tall ball joints (most don't), they won't address the camber gain issue.
Camber gain can only be changed by lowering the control arm mounting (Guldstrand), a taller balljoint, or taller spindle. The taller spindles all seem to come with built in 2" drop. That leaves the tall ball joint or Gulstrand mod. But in actuality Pozzi's testing has shown the the combination of Gulstrand AND tall balljoint produced the best camber gain. http://pozziracing.com/proforged_first_.htm. However, this increases bump steer. This can be corrected with a taller outer tie rod.
Since you're looking at doing both front and rear, you might want to look at Ride Tech's Street Grip suspension. The only thing it doesn't address is the tall outer tie rods. It has dual rate front springs along with adjustable shocks should give it a decent ride, while significantly improving handling.
