hi Derek!

good investigative reporting!  i'm pretty inactive on the list but wanted
to throw you a note on the front vs rear options you are looking at with
the increased spring rates you've found... it's very much a safety issue.
i would have to agree with the man that said get the set of 4.  forgetting
differences in ride height, with unmatched spring rates the front and rear
ends will not work in unison, potentially throwing the van into handling
fits on unique surfaces that may not occur frequently but when it occurs
could be a handful.

from a different standpoint, unless you want to turn your van into a racer
that is airborne quite a bit of the time, you'll achieve better off road
traction with soft spring rates that allow the tire to hug the ground more.
 the hard spring rates will be an advantage when coming down hard from a
mogul at high speed if that is your style of driving.  the vanagon seems to
be more of a crawl-ly traction vehicle that shines when it has lots of
suspension travel and soft spring rates.

lastly, aside from the teeth jarring ride aspect of your proposed changes,
it will place greater stress on suspension parts and body joints.  cabinets
will rattle loose more as will seam welds.

if money is a concern, you aren't high speed 4-wheeling, and value the ride
quality and body integrity of your van currently, my conclusion would be to
definately stay with the lower spring rates.  they will actually give a
traction advantage....  but it's just an opinion.

-dan