What is torsional stiffness and why is it important for vehicle bodies?

Torsional stiffness measures a body's resistance to twisting, typically expressed in Nm/degree. Higher torsional stiffness improves handling precision and predictability, reduces body flex that affects door alignment and sealing, enhances ride quality by allowing suspension to work properly, and reduces NVH issues like rattles and squeaks. Modern cars target 20,000-30,000 Nm/degree; sports cars may exceed 40,000 Nm/degree for sharper handling response.