The Subaru EJ series of engines certainly offers a long and storied history of tuning results. Well before everyone went turbo Japanese tuners were getting monster output out of the boxer four-cylinder literally decades ago. It continues to impress well into 2021.

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This is a 2019 Subaru WRX STI with a built motor from GermanTech Motorworks. Johnson Tuning did the software work through a Cobb Accessport V3.

A very nice mod list:

IAG Performance IAG900 Long Block
GSC Power-Division 272 Cams
Extreme Turbo Systems Rotated Kit w/ GTX3582R Gen 2 Turbo
Extreme Turbo Systems Header
Injector Dynamics ID1700s
2 Walbro 450 w/ I-Wire Wiring
Process West Intake Manifold
Extreme Turbo Systems 4” Intercooler
Flex Fuel Kit
Johnson Tuning Tuned w/ COBB Tuning Accessport V3

And monster power from the 2.5 liter motor:

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553 awhp 415 wtq on 93 octane
757 awhp 583 wtq on E85

If someone says E85 does not make a difference over pump fuel, show them this graph. This STI is making over 200 more horsepower at all four wheels on ethanol over pump 93 octane.

Not that the car is any slouch on pump gas with 553 all wheel horsepower. Flex fuel ability provides quite the bonus and versatility.

Awesome build!