This is a spring pack that replaces the overload spring, and will add 2 inches of lift with out a block. This is very easy to do. It also feels a little more like a truck to me. So I thought Id do a little how to...as my directions look like the one I got with my Titan. lol
The directions that came with the spacer are very good so I won't go it that to much.
1) you need these things....
sockets..19mm, 18mm, 14mm,
4- 6" C clamps, vice grips, floor jack and stands.

1) Jack up at frame rail, support with jack stands. Remove wheel, move floor jack under axle you are working on.
2) Remove lower shock bolt ( 19mm ) and let shock hang freely
3) With the axle supported by the jack, remove the U bolts and spring plate ( 18mm )
4) C clamp the leaf spring together, this will make the through bolt ez to do.
5) jack up rear axle, watch for brake lines when you do this. You will need @ 5 inch to remove the through bolt.As well as the overload spring.
6) line up the new springs with the new bolt, you will be able to squeeze the spring by hand enough to get the nut on the bolt. DO NOT USE THE BOLT TO TIGHTEN THE SPRINGS !!!!!! It will strip very ez. Use the C clamps to tighten the springs, alittle at a time going from side to side. Do not over tighten the 14 mm nut, I did hand tight and a half turn.
7) Lower the axle till it touches the spring pack nub. You will be able to slide into hole by hand.
8) put u bolts back on..TQ to 80ft
9 ) use the floor jack to line up the lower shock bolt, TQ to 90ft

Put the wheel back on and your done.
If any one wants o do this and live in the Denver area, pm me. I would like to help out.