Cars registered in Japan must meet very strict and comprehensive tests, initially after 3 years and then every 2 years. The cost of complying with these test standards can run as much as 30% of the vehicle value. There are almost no cars over 6 years old running! Cars are recycled early, over 4 years old, the owner has to pay the yard to recycle!
.... the result is a lot of good engines being recycled or retired prematurely.
These engines are not street-legal (in US). The Japanese emission standards are tighter than the U.S. but emission controls are totally different.
.... some Japanese spec engines have higher compression and about 10-15% more horsepower, compared to U.S. engines.
These low mileage engines from Japan, however may have been sitting for a couple of months, and the internals are usually dry or rings may be frozen. We oil the cylinders and turn over the engines when we receive them. Engines are checked, but there is no way to guarantee against oil consumption or low compression.
There is absolutely NO WARRANTY on these high-performance engines.
.... we recommend “refreshing”- putting at least new rings, head gasket, timing belts (specially for the older units) and cleaning the oil pan and pump. This assures you that the engine you are installing have no maintenance problems."