Leaning the shock in makes the suspension softer. Standing it up makes it harder. The upper mount holes allow finer adjustments while the lower holes on the arm make a bigger difference. The more the shock is stood up, the more linear the shock will feel. As you lay it down, it becomes more progressive. Either way, the shock position is just another way to fine tune your suspension and doesn't neccessarily replace spring rates.
Team EAM // Gravity RC