Torsion Bars... Best Diameter for a Lowered Street / Autocross car?

I checked the range of travel on my suspension, it’s not an issue, the ball joints are fine, they operate well within their capabilities and are not bottoming on anything.
Same here. I even removed the shocks and the T-bars and the lower bumpstops,and cycled the steering, cuz I wanted to know. The Moogs were happy.
In the end, I raised my K, a half an inch higher off the tarmac, cuz with street tires and on the street it's no big deal, the car is just as much fun, because the tires are by far the limiting factor.
And because of potholes. Our city streets have potholes; lots and lots of them, and I occasionally hit one, and it's nice to have the extra suspension travel.
Plus I am 20 years older than when I first started ,lol, and them RX-7 seats ain't as cushiony as they once were,.