Yes, sir. After you put on the shackles, the system will release air from the rear air shock and bring you right back down to where you started. The same goes for the front on the torsion twist, although I believe the fronts shocks don't carry quite as much weight so you might overcome it with enough lift on the bars.
So here's the deal: The air ride system was designed to keep the entire truck level at a preset ride height. Chances are pretty good that with a working system your truck still rides level without severe rear droop seen in many of the older expos.
There used to be an "off-road" mode that raised the entire truck about 1-1/2 inches and stiffened the suspension (seems a little backwards to me as offroad you would want higher and softer, but whatever). That function was deleted from the computer system after 96.
The height sensors are not load bearing. They do not have any adjustments, but it is not difficult to reposition the sensor mounting points with a piece of flat stock and couple of bolts. Moving the attachment down will make the air ride system think the truck is too low and consequently raise it up. It is a direct ratio, so moving the sensor down a couple inches in the rear will give you a quick two inch lift. Fronts should be no more than 1-1/2 to avoid stressing the CV axles. Would be an inexpensive (like under $15) and easy mod that gives you the lift you want without losing any overall travel and likely not anywhere near as harsh a ride as you might get from cranking the torsion bars. It will also save you rear springs from flattening out or potentially inverting with longer shackles.
OR you can ditch the air ride, crank the bars, shackle the rear, and get longer gas shocks for the front and rear.
Either way will acheive your desired results.
