is terrible about not telling you things you need to know. Here are a few tips that might help.
1. Be sure to lubricate all the bushings and bolts going back in the springs.
2. If you can, find some 14MM locknuts to replace the stock nuts on the spring bolts. Just tighten them barely snug. You don't want to bind the spring. They need to pivot to work properly.
3. When installing the flip kit lubricate the threads before installing the stover nuts. WD-40 is fine. Otherwise they may gall and seize going on. these need to be tight but not back breaking tight! You are compressing the plastic sleeves between the leaves as you tighten. You don't want that over done. I would tighten them, drive the truck a ways and recheck them.
4. You will need a 27" shock to work with those springs. A bilstien 5100 is a good match. The Bilsteins All-pro sells to use with these springs don't work as they are 24"
5. There are two clips that hold the E-brake cable on the stock spring. On the expo spring there is no mounting point for the last one. You are probably better leaving it unattached. Otherwise the cable may not reach at full droop.
6. Watch the brake lines and wheel speed sensor wires when you sepaprte the suspension. They will reach but don't go too far.
7. If you have never done this kind of work be extremely careful jacking and securing the truck! You will have to jack the rear pretty high to separate everything. Remember that the E-brake will not hold the truck since you have the rear tires off. The truck can easily swing side to side and fall. You can do one side at a time, but the pin in the spring will be harder to locate since the axle will be cocked. Be careful!
8. Before I installed my springs I took a wire brush and knocked the loose paint off. It comes right off so it just takes a minute, then I cleaned and repainted them. It will keep them from rusting later.
9. You may end up with DL vibrations after the install. You would be wise to measure and record your DL angles and the pinion angle before you start for future reference
10. Save the OEM steel cup washers off your old shocks to use on the new ones. They have a special lip that fits into the upper shock mount to center the shock rod. The expo spring will move the axle approx .75" to the rear which will make the alignment a bit harder. With the OEM washers though you can get the right fit with a little care.