I'm looking for a means of leveling the back out with all the weight I'm packing around. Currently I'm on a set of 4.5" springs. So I could be looking for a complete new set of springs in the 3.5"-4.5" range. I could use a set of 4" springs for the front with my existing springs in the back or I could probably make it work with a set of heavy rate 4.5" springs for the back.