sway bars reduce roll, but they also reduce grip. a stiffer sway bar translates to reduced grip, hence why if you want a normal car to be more free in the rear you stiffen the rear sway or loosen the front sway. People put big front bars on subarus to counteract the soft suspension up front which lets the front end roll over and create unwanted positive camber and caster. Instead of going to a big front bar, it makes more sense (physics-wise) to do an anti-lift kit and a smaller front sway bar