I swapped in a Z28 bar myself many years ago when I also put on Hotchkis lowering springs (previous springs were worn out stockers with cheap parts store spacers inserted), a stock rear sway bar, and a pair of F41 bars (didn't have the GP cross brace up front yet, have one now though). I don't know how much difference each individual part made, but it feels like it's on rails compared to when I first bought it (old springs, tiny sway bar, worn out body mounts, rusted out frame, etc.).
We're in the process of building a barn, and soon as it's car-ready I'll get that sucker in there and get back to work on it (clutch issues + other things left to do before it's really road-ready).