Lifting a suspension can be easy or difficult. It really depends on the hardware used and tire size/weight/hp/torque considerations.
Lifting a torsion bar can be a difficult thing. The torsion bar is the 'spring'. Twisting it will lift the vehicle, though its not really an acceptable thing to do. The bar is designed to twist during cycling. If you twist it beyond the acceptable memory of the material, you will fatigue the bar and it may shear. Take your arm and twist it to a static point with your feet flat on the floor. By twisting your arm more, you raise to relieve the pain in the shoulder; however, you are still twisting the shoulder up, thus causing a lift. If you twist it the other way, you are relieved of the stress in the arm. Same for the torsion bar. The bar only twists slightly in the factory configuration and the limits designed in the suspension. That is why many aftermarket mfrs provide drop brackets to lift a torsion bar suspension. They just relocate all frame mounts lower. Since vehicle mfrs have changed many of the points, lowering them interferes with the frame itself, so aftermarket has come up with a way around that with longer knuckles between the ball joints. With the addition of the rack and pinion steering, this also supports keeping that in the original location.
About the best way to lift a torsion bar designed suspension is to redesign the torsion suspension to fit the height you want. You will be relocating the frame and suspension points, lengthening/shortening arms and bars, etc. but in the end, very expensive. Or replace the torsion bar with a different spring configuration which may lead into redesigning the control arm(s). The result is still redesign and expense. Or swap in a straight axle which provides more work and thought in the process, and mainly cost is little compared to the other options (depending on skills and hardware availability). What axle to survive tire size/hp/weight of vehicle. What kind of suspension, leaf or coil/links. If leaf, what axle has appropriate leaf mounts locations, etc for an easier swap. If coil/links, separate coils and shocks, integrated, or air/nitrogen shocks only. Coils really needed. Links, how to design them. Again, geometry is a consideration. Go with 3 link or 4. Expense can rise here with the available aftermarket suspension components.
Best thing to lift a torsion bar suspension, is probably not to do it. Look at other ways to gain tire clearance with wheelwell trimming, body lift (slight), and like someone else suggested, swap in a heavier stock unit for the lighter version. If you swap to a heavier torsion bar, might as well look at the axle shafts (or front driveline) themselves as well. Adding larger and heavier tires/wheels, you'll need larger brakes, thicker axle shafts, bigger cv joints, and shocks.
Now getting travel out of a independant suspension is another thing all together.
