The 2020 WRX STI S209 may resemble the rally sedan you can buy at Subaru dealers across the country, but it's not actually a Subaru. , it's actually an STI—not a Subaru.
The S209 is so significantly modified compared with a regular WRX STI, its assembly has to be completed at STI's facility. Each of the 200 S209s planned to be built start life as regular WRX STIs on Subaru's regular production line, but upon completion, they're sent to STI's facility for final assembly. There, STI fits upgrades including wider fenders housing 19x9-inch BBS wheels with 265-section Dunlop track tires, drawer stiffeners, and a clever flexible front strut tower brace. The S209 also gets a significantly revised version of Subaru's stalwart EJ25 flat-four that's been cranked up from 305 to 341 horsepower. that the S209 even had to be homologated for sale in the US as an STI rather than as a Subaru.
Why go through all this effort? As Jalopnik explains, it has to do with the production standards for regular Subaru cars. For example, the Japanese company has requirements on how much space there is between a tire and bodywork. That requirement could force STI use a smaller tire size or a different alignment than what it wants. Building high-performance models in house at a separate factory means this isn't an issue, though.
STI has built limited-run high-performance cars at its own facility before, but the S209 is the first time one will come to the US officially. Despite what the name could imply, the WRX STI is really just a regular-production Subaru.
Given all of this, expect the S209 to be expensive. You thought the $50,000 WRX STI Type RA from 2018 was too much? The S209 probably isn't for you then, though Subaru has yet to announce pricing.