I lived in Japan for 3 years.  The problem is the annual inspection.  It's
expensive. They take the car apart to check everything.  If there's any
rust, it's an automatic failure.  Rust is a BIG problem due to the salt air
environment (it's a chain of islands).  Public transportation is used to
much greater degree than most US cities and towns.  Average commute
distances are less; everthing's closer and more tightly-packed together
there.  I can see many reasons why low mileage JDM motors are so plentiful.
Excellent design, higher performance, longer-lasting engines in car bodies
that don't last as long there.

Mike B.

From what I gather in japan they make it really hard to keep an older car,
like the registration goes up dramatically or something, so they're usually
getting a new car every few years.  Of the few JDM engines I've gotten they
all seemed like they had 50K max on them.

Scott