re:  I was thinking about running my Syncro without a
thermostat ...

For many engines this is specifically prohibited--something
about the pump system needs the resistance provided and the
engine might overheat without it, i.e. you may get LESS
coolant flow.  Don't know waterboxer specifics.

There are also some general, shade-tree reasons for not
doing this:

1.  Slower warm up is bad for any engine:  thermostat
promotes fast warm up.
2.  All us shade-tree types know computers are mysterious
and we heard somewhere the fuel injection software is
programmed to expect a specific, constant temperature.
3.  More computer mystery: mixture is rich at first (like
choke) and then goes to normal after a set time expecting
the engine to be warm.  If it isn't, ... (runs bad).
4.  How many times do you want to take the system apart?
Why not just once, i.e., to replace the 'stat, instead of
twice, once to take it out, and once to put a new one back
in?