I just spent some time searching E body torsion bar sizes on the web. I took a few screen shots of people writing that when running 60 series tires and a SB, and GOOD shocks, that the 1.12"-1.18" bars are still comfortable on the street!! It appears that the 60's absorb some of the road texture.
I also read that the difference between the .9" and the 1.06" bar is not that noticeable.