There are so many varibles here. One that i think was missed thou is the relationship of the Roll Center height to the CoG? How do the drop spindles affect Scrub Radius?
Generally the the closer together the CoG is to the RCH the less roll angle the car will experience, the more you raise the RCH it will tend to cause a jacking effect which will nuke a mopars caster gain in a corner, so preferably you would want to lower your CoG if possible, to get a tighter distance. So my question is do the Drop spindles drop the CoG without significantly raising the RCH? If so then they would help handling.
Next question does the raising of the axle centerline along the kingpin inclination angle effectively change the distance to the centerline of the wheel. If it does it would reduce the scrub radius, which reduces the twisting forces that the tires exert on the steering, which will make the car feel more controlled with reduced steering effort.
Any thoughts?
This was actually already covered somewhat. Lowering the COG is obviously pretty important. But, the drop spindles DO raise the roll center of the car. The bottom line is if you can get your car lower without the drop spindles, you'd be better off. Now, if you can't get the car low enough with the stock spindles (due to larger torsion bars), then you have to look at the trade off between the COG and RCH. Since I originally used my drop spindles to lower my car a full 2", I would say that, on the street at least, I thought the car handled better than when it was 2" higher, despite the raised RCH. But that's just "seat of the pants" testing on the street, not a definitive answer by any means. And, if you aren't lowering the car the full 2", I think the negative effect of raising in RCH will overcome the lowering of the COG. You also have the issue of bump steer.
There are other means of lowering the car. Most torsion bars are offset 30 degrees for preload. However, this isn't really needed once the torsion bar is 1" or more in diameter. The old circle track guys used to clock the torsion bar anchors 30* to achieve a 0 offset setup, but that requires cutting the anchors out and re-welding them. Just Suspension also made a 0 offset bar for awhile, I think it was 1.06", but they no longer make that one unfortunately.
The other way to do this is to install the LCA's at something other than full travel, thereby clocking the LCA's. But since the torsion bars have hex ends, I
believe this changes the offset by 60*, so, you wouldn't have a zero offset, you'd actually have a -30* offset, or 30* in the opposite direction from stock. Depending on the size of the torsion bar, that may not give you
enough ride height. But I may be wrong about that one, maybe HP2 will chime in and correct me if I'm mistaken.