"They improve cornering and handling performance tremendously with no impact on straightline driving comfort."

That isn't entirely true. By having two wheels connected as they are with anti-sway/roll bar, there is slightly less ride isolation. This occurs say when one wheel hits a bump. Without the anti-sway/roll bar, the suspension for that one wheel must absorb the impact. However, with the anti-sway, the other wheel is involved, and with some resistance from the other wheel, there is more force against said bump, which equates to slightly more force pushing upwards to the chassis through the suspension. Also, because the anti-sway is connected to the chassis directly as well, there is some transfer of bumps into the chassis this way as well. This is why some people report slight decreases in ride isolation when upgrading to thicker anti-sway bars.