Ride height has almost NOTHING to do with the tension on the bars. The ride height is controlled by the torsion bar adjusters. If you look at how these work, they change the angle of the lower control arm with respect to the torsion bar anchor. That doesn't change the tension on the torsion bar AT ALL, the torsion bars are not twisted by the torsion bar adjusters, and the weight of the car stays the same, so the same load is on the torsion bars.
Now, if you're bottoming out because your car sits so low, then the ride height does effect your handling. Which is exactly why you should upgrade to larger torsion bars. The higher spring rate will reduce the amount of travel that your suspension uses, so you can get away with lowering the car and reducing the amount of available travel.
Joe summarized it pretty well, 1" torsion bars (or bigger!), better shocks, XHD rear springs, front and rear sway bars, and rebuild the front end (all the bushings and ball joints). I'd use offset upper control arm bushings since you're lowered so much, they'll help with getting a proper alignment. Alignment specs for modern tires should be -.25 to -.5 degrees camber, +3 to +4 caster, and around 1/8 to 1/16" toe in.
And for no reason should you keep your /6 bars. They sucked on /6 cars, they suck even worse with a V8. You can't even BEGIN to make up for them with sway bars. Lowered as much as you are now, I'm guessing that you bottom out your suspension frequently.
As far as drop spindles, you shouldn't need them. Most of the 1" bars on the market now have less offset, so you can get pretty low even with the stock spindles. And the loss of suspension travel is made up somewhat by having a stiffer spring. To really put it in the weeds the drop spindles will help keep some suspension travel, but you have to watch the backspace on your rims. Nothing new, its the same issue with having 15" wheels, with too much backspace you hit the tie rods. It just makes it an issue again for 17 and 18" rims. If you have much more than 5" of backspace on your rims, you'll want to check some clearances.