Over the knuckle gets your tie rod up above the knuckle (hence the name). The benefit is to keep it away from rocks while offroad. If you were to bend a tie rod offroad your tires would be fighting each other. This may be exaggerated but instead of being near parallel | | they could be / \. There are many kits available from various suppliers, you'll have to do some research and see which one you would feel comfortable tackling.