Duriung my sports car racing days, we would change the diameter (stiffness) of the front and rear antiroll bars to adjust the handling in turns. It's possible to change from understeer to neutral handling to oversteer by tinkering with bar diameter. Adding a bar when one was not there before will certainly affect the handling, but there's not much way to predict what will happen without some skid pad testing. Ride height, spring rates, Ackerman, roll center, roll couple, and a bunch of other engineering calculations could probably get into the mix.
Jerry
