I did my own 6-cyl. conversion (to 2.7 liter nominally 165hp) and will rave on
about with scant prompting as others know.  I have never ridden in one of the
factory Vanagon conversions, but I got to see one closely as it came through
NJ.  First tip-off was "I wonder why this staid-looking refrigerator-white
Vanagon has fat Pirelli P-6s on its aluminum wheels?"  That van gave no clue
that it had not come off an assembly-line; there wasn't a wire or a hose that
looked like an afterthought.  Interior was done up in executive limo style:
grey cloth, Blaupunkt controls on a stalk for the rear seat passengers, full
911S instruments.

Top speed was said to be 130mph.

Anyway the Vanagon six conversion is not all that hard, and the result is not
one of those V8-in-the-pickup-bed abortions with no earthly use, but a very
logical next step in the same design direction your van was already headed.
Try it; you'll like it.
B.