"One quibble.  Is the Zetec cleaner?
I've heard that it cannot pass California emissions test.  Waterboxers
properly maintained pass, don't they?"
Look at the engine data on the Bostig website instead of using "I've heard".
Not even close. There ARE NO CURRENT ENGINE CONVERSIONS THAT BURN/SMOG
DIRTIER THAN A WASSERBOXER. None.
Not having the CARB sticker has nothing to do with the Zetec not being an
allowed Calif. conversion option, just like the Subaru 2.5 hasn't.

By the way volks, I've consistently gotten, at worst, 19mpg. My van is 5K
lbs. prior to camping prep. When I drive in caravan I get 24 mpg.
When I drive mountains, 75-80 mph by myself, I get 19. I'm impressed with
it. As Al suggested, I change oil at about 5K mi + filter. Maybe
in the end that contributes more to a recycle problem/pollution issue than
the hard-to-measure benefits of doing so. What I can say is that
I've already taken more trouble free trips in just under 2 years of having a
Subaru 2.2 engine, Than I did in over 5 years of having the TIICO.

YMMV

Bob Stevens
'87 Syncro Westy