[bret]

To clarify...

The design of the control arm has NO INFLUENCE on the core front suspension geometry.

The suspension geometry can only be influenced by the control arm attachment point or the ball joint attachment point. Some hotrodders relocate the control arm pivot point...aka the "Guldstrand Modification" where the cross shaft of the upper arm is moved down by some amount.

Other manufacturers move the position of the ball joint via a taller upper and/or lower ball joint, or a taller spindle. We use both methods depending on application. On the G body / S10 we use a taller upper ball joint to improve the camber curve of the suspension. As mentioned above, we want the top of the tire to lean INTO the turn, not away from it. If the attachment points or the effective height of the spindle does not change, neither does the suspension geometry.

Tubular control arms do not change the front end geometry, but they do compliment it.

MUST you use a tubular control arm[s] to compliment the change in ball joint or pivot point location? No, but the best ones offer several other advantages:

1. optimized ball joint position to re-center the ball joint in its travel at a lowered vehicle height to avoid binding
2. upper ball joint moved back to increase caster alignment
3. lower ball joint moved forward to re-center wheel in the wheelwell
4. better bushings. We prefer delrin.
5. redesigned upper cross shaft to allow easier front end alignment
6. lowered coilover mount to allow a longer stroke unit for better ride quality
7. Strength...many oem arms are fatigued and or rusted. Strength typically becomes a problem during braking...that 3800 lbs you are trying to stop from 130mph is trying to twist those arms right out of the car.

Keep firmly in mind that not all tubular control arms resolve all of these issues [some resolve none]. When you find yourself attracted to a set of arms that are priced at less than half of a respected brand, you may want to ask some of these questions of that manufacturer.