All Scott said is true, but I will add that most cars are set up to have some, to a lot of understeer, where the front end 'pushes'. My WRX, while being more neutral than the outbacks and foresters, was still not to my personal liking and a rear bar increase helped to get it where I wanted it to be. Another thing said above is that winter conditions generate far lower cornering forces and that a very stiff roll setting will tend to give you a 'now you see it, now you don't', lightswitch release in the snow and frozen road conditions. So don't go too big on your bar choices if you value a predictable winter handling car.