The kit does not include rear suspension.
I am no pro, but I'd say go with some Deaver springs(they make 2 different packs for different loads, the F31 is softer, and the G50 is stiffer and made for spare tires, fuel cell, etc). If you want to keep your bed intact, you can flip the stock shackles and hangers and you can run a 2.0 shock. You are pretty much limited to a 10" travel shock, you can fit a 12" but you will need new shock mounts, and even then you might have limited up-travel without bottoming out the shocks.
If you don't mind cutting your bed, you can run flipped hangers, extended shackles, and a longer shocks with a bedcage.
NOW: 2003 Explorer XLT 4X4. 4.6L V8. Tow package with the LSD rear axle.
SOLD: 2007 Ranger XL, 2.3L 5spd, lifted and junk.