Dry cement instead of wet cement...just kidding.
I think the best bang for the buck improvement that you can feel is thicker anti sway bars.
You can get thick 1 5/16", [ maybe thicker? ] that are hollow to keep the weight down. I bought Hellwig sway bars from Summit for my GTO & was very pleased with the quality, the instructions, extra hardware that came with them & the improvement in cornering [ much reduced body roll ].
You can also go to stiffer springs, but a fine line between handling & comfort. Maybe try 1 mm thicker wire on the front springs, retaining the same number of coils.
Good quality shocks that are adjustable. Everybody has an opinion on the 'best' brand....
I prefer rubber, not polyurethane, bushes in the suspension [ except for sway bar mounts ]. I think the extra cushioning provided by rubber is important, especially on cars like the Camaro that do not separate body from the chassis.
You can get tubular upper control arms that have more caster, but might make the steering heavy if manual steering.