Another old thread, but for all of you looking to add a cheap lift to your van there are several options:
Put a larger coil to give you 1.5-2" lift depending on coil. You will have to run a 2.5-3 degree cam to get your alignment correct. The negative part about this is that you will take + caster out of the radius arm which may cause you van to wander more.
Lifting it 1.5 " you can usually get away without changing shocks.
If you would like to do something like this we offer a kit with modified radius arms to increase caster with the lift coils.