only problem with making the trac bar the same length is that the front of the spring isnt flat, and expands as the suspension moves up. leaf springs do not travel in a perfect arc. it also depends on how the spring is built. if i know a truck is going to have a trac bar, i make the front a little bit flatter than normal. cant do it too much though, as it will cause the front of the spring to go negative in arch before the rear, adding stress, and it can wreak havoc on driveline angles.