>| Riddle me this: if the spacer were 12" thick would it compress the
>| spring? I think it would. Therefore, it stands to reason that a 1" thick
>| spacer would, in fact, compress the spring by some amount, IN SPITE OF
>| THE WEIGHT BEING THE SAME!

        The 12inch spacer would compress the springs because you would hit
the limit of travel. Until you hit the limit of travel, the only other force
that will change on the spring is the pull of gravity, but since you are only
increasing the distance from the center of the earth to the center of mass
of the van by maybe an inch, this is negelible ;) The shock absorbs might
behave quite different if they are extended an extra inch at rest, but the
springs will not - from the point of reference of the spring, nothing has
changed.

dave