Which Torsion Bar?

First;You will need more rubber on the front for sure. 235's fit easy on 14 x7s. 245's on 15 x 8s. Unfortunately 15 x 8s are a PITA to fit in there cuz they want to occupy the same real estate as the BJs. So 17s is the way to go.
Once the tires are actually big enough to turn the car then, 1.03s minimum, has worked for me. Sooner or later you will want to lower the car, and then bring the tin-snips along.

I get by with 235s on the street, but I have to slow down. A lot.