Electric water pumps have lot's of benefits now, however there is also
something to be said for keeping things simple.

The electric pump will save gas, increase power available to the
wheels, allow for pre/post cooling system function when the engine is
off(not that useful with vans, but great for drag cars on track night
in the lanes) coupled with a block heater in cold starts you could
arrive at your van with the entire content of the cooling system above
ambient and really cut into your warm-up time and it would save on
engine wear on start...

Anyhow the down side is if the pump fails, you're all done... but
armed with a simple flow gauge or system monitor the risk is
controlled... it's also expensive, and hard to find a pump to run
compared with the stock pump.  It would be nice to lumb two pums into
the system just in case... and so rapidly you've increases the
complexity of the system. Is the added efficiency worth the increase
in complexity? The answer is going to be totally subjective based on
the operator's goals and capability. For the OEMs it is, and is
increasingly so. It is actually much more efficient to generate the
power needed to run an electric over hydraulic power steering pump
than it is run the hydraulic pump all the time, because the average
load is so low... this won't really be the case for a water pump, but
for some situations would make a lot of sense. You might actually
dispense with the t-stat at some point as well if you have control of
both the water pump speed and fan speed.. but again, is this a
realistic thing to do for your average vanagon owner? I doubt it's
worth it.

The power steering pump is though... which is why I have one sitting
here ready to go on my new van.. and dump the old mechnical/hydraulic
one. It also means I can mount both it and the res right next to the
rack and have really short power steering hoses, and variable steering
assist... full on in parking, almost nothing on the freeway, all while
getting a mpg bump(might not be very noticeable but it'll be there)
and a bump in power/torque.   Very nice. If it all works out well,
we'll roll it into a kit for customers.

Jim Akiba