Oh, the swaybars! Just go one bar thicker all around. I tested this when the grip was REALLY high though. What would happen the car would roll so much, that it would dump over too much. So when I needed to transition to the opposite direction it would make the car really weird an unstable.
Try the roll center changes and the spring/shock change on the back first though. I'm pretty sure those will be more noticable change than the swaybar, especially if your track is low grip.
-Korey