Current Suspension mods
By far the weakest link in the stock Trans Ams suspension are the shocks. They are soft and severely lack rebound damping for a car this heavy. My first upgrade was a set of single adjustable koni yellow shocks (only the rebound damping is adjustable). This only made a night & day difference in how the car rode and handled. I have the shocks adjusted halfway on the rebound damping, but may increase the damping further.
Also installed is a larger front swaybar to further reduce body roll. The stock 29mm bar just wasn't enough. I've got a 35mm ST swaybar now (I have pics of the two bars side by side that I need to scan and upload at some point). Steering response is much improved and roll is nonexistant on all but the hardest cornering (and then it's very minimal still)