what size torsion bars should I buy?

I would never put anything smaller than 1" on any Mopar ever again. The original bars were for bias ply levels of grip and aren't even enough for old design and compound radials like BFG T/A's, let alone modern design tires and compounds.

The catch is that if you run them with cheap shocks like KYB's the ride quality will suffer. But that's just physics, the dampening rates of the shocks have to be matched to the spring rates of the torsion bars. If you do that by running bilstein rcd's, Hotchkis fox's, Vikings or similar shocks designed for use with larger bars the ride quality is great.

A lot of people run the 1.03's and love them, there are several threads on this board about them. I ran 1" bars from Just Suspension on my small block Duster for awhile and found them to be too soft even when I had 225/60/15's on the car. Sure it was a big handling improvement from stock, but there was still a ton of body roll. I upgraded to 1.12" bars, but my car is set up for aggressive street handling and autoX and obviously isn't everyone's cup of tea.