Blackstone Labs is a reputable engine oil analysis company. 2017 study using Subaru engines.
"Instead, we want to look at the average wear rates from a lot of different engines
of the same type. This eliminates the statistical “noise” from individual samples,
and gives us a more accurate picture of normal wear. For example, shown at left
(Fig. 1) are the universal averages for the Subaru EJ 2.5L Turbo engine, used in
the Impreza WRX STi and Forester XT. We have more than 5,000 samples from
this engine in the database, at an average oil run of ~3,900 miles."
https://www.blackstone-labs.com/wp-content/uploads/2018/09/Aug-17-ENG.pdf
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"Instead, we want to look at the average wear rates from a lot of different engines
of the same type. This eliminates the statistical “noise” from individual samples,
and gives us a more accurate picture of normal wear. For example, shown at left
(Fig. 1) are the universal averages for the Subaru EJ 2.5L Turbo engine, used in
the Impreza WRX STi and Forester XT. We have more than 5,000 samples from
this engine in the database, at an average oil run of ~3,900 miles."
https://www.blackstone-labs.com/wp-content/uploads/2018/09/Aug-17-ENG.pdf
