yeh rebel thats the actual procomp part number: EXP 13120.
do a search for that exact number and you can find them for around 35 and up. i personally got mine off amazon. as for install its easy and straight forward. jack it up stands on frame, support jack under center of axle, lower bolts on shocks, U bolts on axle, use support jack to raise the axle, grind off center pins on leaf pack, use the supplied 3/8" bolts, add the add-a-leaf between the 3 upper leafs and the thicker overload spring, tighten centering pin and reinstall in reverse