Whenever I've driven an automatic vanagon, especially a Westy, I always
have the feeling that it is dragging.  It's not that the peak power is not
there, but whenever you choose your own shift points, you can do a better
job than the automatic can do.  The real difference is in hilly country. 
You can drop to third gear in a manual and hardly miss a beat, but an
automatic vanagon will really slow down going going uphill.  For some
reason, I've always found that the VW automatic is hard to manually
downshift, more so than American automatics.  

I had an automatic EV 5-cyl. and a vangon 4-sp. at the same time.  On flats
the EV would leave the vanagon in the dust.  However, I had a much easier
time crossing the Rockies in the 4-sp. vanagon despite a less powerful
engine, because I could shift at the optimum moment.  The EV automatic
really struggled up the steep mountains.

Not everything about automatics is bad, though.  An automatic will often
last almost forever with minimal (or no) maintenance, while manuals will
require a clutch from time to time and finally a very expensive tranny
rebuild or replacement.  Still, I'm really sad that VW decided not to bring
the 5-sp. EV into the US with the VR6.  Canadians have all the luck.....

Bill
87 Westy "Wendy"
87 Syncro Westy "Hellbitch"