Hotchkis sway bars are hollow, so bigger diameter does not necessarily equal a stiffer spring rate. The Hotchkis bars are likely stiffer than a lot of the bars out there, but its not as much as the diameter would lead you to believe. They are a lot lighter though.
New t-bars and shocks would be the only way to go, running this set up without upgrading those would be a large waste of money, especially if you've got stock shocks.