Also tire pressure, average load, whether you run with windows open or shut,
tire type, wheel alignment, temperature (e.g. drive during day or night).  I
would expect all the Vanagons to be within the 15-20 mpg range, including mine
with six cylinders and not-well-dialed-in carbs.  I would find it more useful
to get anecdotes of the form "My mileage went up/down by x mpg when I ..."
so that we get some idea of the cost benefit of various changes.  I'm especially
interested in items like cutting off the rain gutters at the edge of the wind-
shield, adding the $79 spoiler that JCWitless sells, adding 2-in. wide "ears"
at the air intakes for better engine cooling, converting to or from FI, in-
creasing or decreasing tire pressures, fiberglasing in the grill (*top* grill
for you waterpumpers), lowering the ride height.  The absolute numbers are 
going to vary by a large percentage of a small range, driven by differences in
driving style that can't easily be defined much less controlled ("I can't go
faster, honey, I'm doing a test for my friends on the list").  But the magni-
tude of the change would be helpful to know, wherever it exceeds noise level.

Here's one:  My mileage was never more than 19 with stock 2.0 FI engine.  It
went down dramatically in town, but only by a few points on the highway, when
I put in the Porsche 2.2 liter six with carbs.

B.