is it ok to adjust torsion bars to change my cars stance.

twofosho said
Raising the spindle hub axis relative to the ball joints (dropped spindles) will NOT have an effect on the roll center or change bump steer. Raising the tire contact patch relative to the kingpin axis with a drop spindle WILL change the amount of scrub by moving the kingpin axis intersection with the ground plane inboard.

Lowering the front of the car relative to the rear WILL reduce the effective amount of caster.

The roll center is changed, as well as the bump steer. The roll center changes because the angle of the control arms change relative to the height, and CoG, of the car. It changes the relationship between the ball joints and the control arm mounting points at a given height, which changes the roll center.

The bump steer changes because the steering arms postion changes with regard to the spindle location, by the full 2".

There was a pretty extensive discussion on this over at Cuda-Challenger, by guys that understand suspension better than me. Complete with computer analysis (page 5)

http://www.cuda-challenger.com/cc/index.php?topic=72437.0

CUDA69 said
After sleeping on this I have to admit that yellowdartdave has a point here. Experience may trump basic theory sometimes. Even though the "rotational" spring rate has not changed the practical one may have. Here's my thinking on this: (An extreme example just to make the math easy)

If you start out with the lower control arm horizontal to the ground, and it was 12 inches long, and you put 1000 pounds on it, then it would transfers 1000 FtLbs to the torsion bar. Then you crank it up so the LCA is now 30 degrees to the ground. Even though you still have the same 1000 pounds on it, the torsion bar would only see 866 FtLbs because the force is only vertical, not tangential like when using a wrench.
As far as the driver is concerned, the perceived spring rate has increased 16%.

OK, so the LCA does't move that much, but even a 10% increase is very noticable. What do you think?

I can see how you might think this, but your physics is a little off. The lower control arm does not change in length, and the force applied does not change. The ground being parallel is of little consequence, because the force is applied on a rotation. Your frame of reference isn't the ground, its the torsion bar.

Think of it this way...Does the angle of the handle of your socket wrench change the amount of force you apply to the bolt?