Stiffer steering? Where did they set the caster at?
Off-center steering wheel? Need to put it on the alignment machine/rack and make the tie rod adjusting sleeves the same distance apart from their ends of threads. Toe-in can be set correctly but the sides can be uneven on the threads. Nothing related to the torsion bars.
Is the car now sitting with the rocker panel parallel to the road surface, as it did when it left the factory when new?
Check the fine print of the "Shop Warranty" on your repair order. See how long (time and miles) the warranty is for. Document on the back of the RO that you mentioned the off-center steering wheel to the manager (time, date, and miles on the car when it was mentioned). THEN, toward the end of that warranty, re-address the issue with the off-center steering wheel (that got no better) and the stiff steering.
Most OEMs did not want to do a "warranty alignment" on new cars with less than 3000 miles on them. Wanting everything to get used to each other, for example.
Which torsion bars did you get installed (and why)? Any other things done to the front suspension?
CBODY67