In front, I like the Hollow 3rd gen F bar because it stiff and about 15lbs lighter than a solid bar. They came up to 36mm in diameter. I got mine from a junkyard years ago. You can identify them by the the drain holes near the eyelets (and the light weight once off the car). They are probably harder to find now, but F-body people probably still have them in their garage.
A big rear bar helps the car turn, but a big stock location rear bar will eventually crush and bend the Lower control arms, so new stronger LCA's will be needed. I ran both the Herb Adams and ATR bars (both about 1.5") and liked the reduced understeer. A pro touring style rear swaybar does not need upgraded LCA's so though it costs more that a stock location bar, the total cost will be less.