Sorry! I know I'm new but I had to ask.. do our cars come with front and back sway bars? And if so, would upgrading to something like this really matter?

http://cgi.ebay.com/ebaymotors/ws/eB...tem=2442425492

I thought I remember reading about them a while ago, but I clearly remember that you can adjust them to different toughness. like hard, soft, etc.. or were those something completely different? Well just wanted everyone's opinion on that modification. Worth the money? or nah, spend it on something else..