Significant improvement, probably the best 'handling improvement' out of any suspension modification other than subframe connectors and a modern radial tire. My 69' Road Runner handles like a modern car, with the Hotchkis suspension & properly tuned Fox shocks. Hotchkis tuned all their components on track cars, torsion bar suspension works when it's designed properly.

I've previously owned a Corvette Z06, SRT 392 Challenger, and Saleen Mustang as a reference.