Different racing genres use different levels of Ackerman. With drift cars, for example, it’s not uncommon at all to run zero Ackerman and technically negative or reverse Ackerman would be better/faster because of the slip angles involved. But even with drift cars most drivers don’t run negative Ackerman because of how different it makes the car feel compared to normal.
High speed performance is its own thing entirely because the steeing angles are reduced. Ackerman gets more important as the steering angles get more severe, so high speed maneuvers reduce the impact of Ackerman to begin with. F1 cars for example have TERRIBLE steering angles. Yeah at 200 mph they perform amazing, but navigating a parking lot would look like a scene from Austin Powers.
But those are race cars, not street cars. It’s a different bar if you’re still street driving.
So you had them x-rayed? Or did destructive testing to determine the yield strength on a set of test arms?