Just a comment with regards to torsion bar tension. As you tighten or loosen the torsion bar your are only applying the load of the cars unsprung weight to the torsion bar. As soon as the weight of the car is off the snubbers the torsion bar is carrying that weight and the tension does not change while the car is at rest. As you turn the adjuster screw in all you are doing is lifting the car and gaining clearance.(The tension does not change because it's still only the weight of the car that is loading it up)
The torsion bar is just a spring that twists (hence torsion) so the only time you increase the tension of the the spring would be if you increase the weight of the car or bounce the car while driving.(over speed bumps) If you raise the car height and allow the car more suspension travel you will load the torsion bar more than intended. If you are worried about a failure, simply raise your lower snubbers or install longer ones to restrict the travel. (ie - if you crank the car up an inch......raise your snubber the same)
The only way to stiffen the suspension, as with any type of spring, is to replace the torsion bars with stiffer ones. Hope that helps. Anyone see any flaws in my theory? Seems logical to me.