Quality of a Used Engine is determined by how well it was take care of, which is a big question mark for most vendors. Imagine a salvage yard in United States spends all their time sourcing vehicles from auctions, insurance companies etc then 80% of the their employees time is spent on dismantling and cleaning. Gurus of Automotive industry have been recommending to buy Used JDM Engines for the past decade. Japanese used motors last long because mileage is restricted in Japan and even if these engines are not tested, failure rate will still be around 1-2 % compared to a high failure rate of over 30% on Japanese motors from Salvage yards.
We all know that there is no option for some people living in remote areas where there is no one selling Japanese motors but there is a big Company in Houston, Texas called Engine World Inc that ships containers of Used Japanese motors from their office in Osaka . They ship these JDM low mileage engines to all over United States & Canada. They sell Engines with six months warranty and transmissions with three months warranty. This sounds like a steal ! Low mileage, tested and great warranty really sounds good. Junk Yards don't bother about carrying a huge inventory so if the engine goes bad they can't offer a replacement at all. Japanese importers carry a huge stock of engines in demand so even if an unlikely event if an engine fails they can immediately exchange it.
It is logical to spend on these low mileage motors imported from Japan because Japanese engines last long as very few Japanese people drive more than 5 years and average mileage they put on these motors is no more than 40,000-50000 miles.
We have therefore found these JDM motors to be the most reliable motors that actually do a good job and last long !