Q: What handling gains come from a stronger rear trailing arm?

By replacing a flexy rubber-bushed link with a stiff billet arm on sealed spherical bushings, the rear wheel stays where the geometry intends under cornering and braking loads. That tightens turn-in response and improves stability, giving more consistent, predictable rear behavior as you push harder. It also adds durability. The gain is about precision and control rather than outright grip, which you build with tires and alignment.