Coming from 8th Rallycross we use anti-rollbars as a tuning aid all the time (you pretty much won't find a rallycross buggy that doesn't have them fitted at both ends).
You can use them to do is shift where the grip is and balance the chassis. Adding a thicker ARB at either end of the car will decrease the grip at that end of the car, effectively adding grip at the other. If you need more turn in an general steering? go with a lighter ARB up font, or thicker in the rear. You'll loose rear grip and add I'd grip up front, so the front end will come in faster and the back will swing round more. Car diving into the corner really hard and the back end coming loose, I'd go thicker up front or thinner out back to remove some of the aggression and shift some of the grip from the front to the rear.
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