Swaybar weight reduction by Hellwig, went to tubular construction for larger diameter

I was just reading Mopar Muscle, April 2012 issue, and they have an article on the wieght reduction of a 1968 Valiant.

The tubular antisway bar is both stiffer and lighter than a solid bar

http://www.hellwigproducts.com/products/street-performance/tubular-sway-bars/