It's been 15 years since the STI edition of the venerable Subaru WRX sedan (and for a brief, shining moment, hatchback) first made the trek across the Pacific to populate American showrooms. From the same mold as the brand's successful World Rally Championship cars, the WRX STI represented Subaru's tuning pinnacle, and, despite its differences from what would appear in the Japanese market under the same banner, it quickly became a go-to for anyone seeking to build an all-wheel-drive powerhouse for the street.
Over time, however, Subaru began to shift its focus from the tarmac-and-gravel crowd to asphalt in terms of its motorsports aspirations. Although it kept a toe dipped in the RallyCross scene, the most serious versions of the STI began to crop up on starting grids as diverse as the N rburgring and the Super Taikyu Series. A similar change could be observed in the diverse array of special-edition models unleashed in both Europe and Japan, with driving dynamics more tuned for the circuit than the special stage.
The ultimate culmination of Subaru's performance pivot can be seen in the 2019 Subaru WRX STI S209. The very first S line model offered in the U.S., it brings with it a personality distinct from that of its standard STI sibling, one that trades its factory hot-rod roots for more sophisticated modern racer regalia.
Not Quite a Subaru
Previously, any sampling of Subaru's S line required a trip to Japan, because that was the only place Subaru saw fit to hawk its super-tuned S201 through S208 special editions. The 2019 model year flips the script complete, with the entire 209-car allocation of STIs available exclusively in the United States.
Getting here was a long and complicated process, as it required STI to be homologated as an independent manufacturer in the eyes of myriad federal agencies governing American automotive imports. The reason? All S209s are plucked from Subaru's Gunma assembly line and then shipped to STI's nearby Kiryu HQ, where final assembly results in a vehicle different enough from the traditional WRX that it must undergo its own crash testing and emissions certification. As a result, depending on where you look on the S209's body and paperwork, you'll see a mix of both Subaru and STI under the "manufacturer" heading.
If this sounds like an expensive and extensive hassle, you'd be right, and it might seem unusual for a smaller house like Subaru to throw this much investment at what is essentially a boutique compact performance car. Both the mother ship and STI itself became convinced of the S209 project's merits after former WRX/STI general manager Matsuo Takatsu immersed himself in the massive enthusiast culture surrounding the model, particularly in the United States. Now overall GM at STI, his experience was the catalyst in taking the S line international.
The Difference Is in The Details
In the eyes of Subaru—and federal regulators—the S209 is considered STI's "complete car," a vehicle that has been conceived, designed, and executed entirely under the Subaru Tecnica International's auspices. While this is nothing new on the JDM scene, in which more than 13,000 STI-influenced models have been sold since 1998, it's an entirely new branding exercise for American customers.
At first glance, there's not much to separate the S line from your standard street-tuned STI. Since it borrows the carbon-fiber wing from Subaru's Type RA edition and sits on 19-inch BBS rims, it's not until you notice subtle changes like the wider track, front under spoiler and canards, and buffed-out body work that the overall effect of the S209's aero-focused makeover begin to sink in.
Lift up those side skirts and the real details begin to make themselves known. Drawing deep inspiration from its endurance racing experience—especially at the previously mentioned 24 hours of 'Ring—STI laser-focused its development on making the sedan as responsive to driver inputs as possible.
Highlights include the flexible draw stiffeners installed at both the front and rear strut tower braces that improve yaw response even compared to the Type RA by fighting chassis flex while pre-loading the suspension and ensuring better turn-in. Lateral links feature spherical joints and work together with unique Bilstein shocks and 10mm lowering springs. While the latter doesn't actually change the ride height of the car due to the presence of 265/35R19 Dunlop SP Sport Maxx GT600A tires, the installation of a lightweight carbon-fiber roof panel lowers the center of gravity by 2mm.
Further updates are found under the hood, where the car's turbocharged EJ25 churns out 341 hp at 6,400 rpm, along with 330 lb-ft of torque at 3,600 rpm. Although not a match for the 2.0L used in past Japanese STI models (and retaining cast, rather than forged pistons), the 2.5L matches the S208's clutch, exhaust valve, and flywheel specs and adds a new air filter, intake design, higher-flow fuel injectors, and larger turbo capable of pushing 18.9 psi.
As impressive as that list of tweaks and updates might be, it's in driving the S209 that the benefits of the STI's extensive racing acumen make themselves known. Despite sharing an aging platform with the WRX STI, the S line dials out all the street car's jitter and crash and instead substitutes a smooth, playful, forgiving character, as we experienced firsthand last September.
On the twisting New England roads leading to Palmer Motorsports Park, the S209 reminded me of the glories of hydraulic power assist as it glides gracefully over asphalt that was, on occasion, less than polished. It's also remarkably quiet despite the aggressive rubber compound down below and the equally belligerent aero antics pasted front and rear.
It's at the track where STI's limited-production marvel truly made us a believer. Power delivery is linear despite the larger turbo, and it's difficult to pinpoint any gaps where torque is unable to rise to the demands of the right foot. With its retuned SI-Drive set to Sport Sharp, and the center differential biasing torque delivery to the rear axle, the S209 moves laterally through longer corners with predictability while providing shockingly agile turn-in for an all-wheel-drive vehicle.
Even when overcooked and forced to reel itself in with its massive six-piston front Brembo brakes (featuring an STI-specific pad compound), the vehicle remains compliant, forgiving the occasional on-track error with grace and preserving your peace of mind as you hurtle at triple-digits speeds from one concrete K-railed curve to the next.
Palmer's long front straight offered the opportunity to test out the S209's party trick, a factory-installed water-methanol spray system for the intercooler, which is activated by pulling on either paddle snugged behind the steering wheel. Temperatures were too low for any noticeable performance benefit, but it's easy to see how this would factor in during a hot July lapping session. Less appreciated is the short shifter. With 10 percent less throw, it's easy to get mixed up seeking out Third gear on the six-speed box and end up instead lugging around in Fifth.
Best for Last
There's no question the Subaru WRX STI S209 is the best track day toy yet from a company that's renowned for democratizing the concept of all-wheel-drive performance. The idea that the S line is a true STI product rather than an STI in track-day drag, is easy to believe once it's been flogged on the closed course it was born to. No mere marketing exercise, the S209 is the real deal, and an impressive accomplishment considering the older technologies rooted in its platform.
How will it play with Subaru fans? With no pricing announced, it's difficult to know for sure. Type RA models traded for $50k, which was a significant ask on top of the base STI, and it's hard to see any realistic window sticker for the S209 that doesn't have Subaru operating at a loss on the limited number that will be imported to the U.S. On its own side, the automaker points to its biggest challenge not being who will buy the S209, but rather, which of its 600-plus dealers will get a crack at a car that will be available to less than a third of their number.
Still, even with a new STI on the horizon as a 2021 model, the S209 sends the previous-generation car out with a bang that proves there's still a lot of life left in the older design. For American Subaru fans seeking the rarest and most athletic edition of the turbocharged terror ever produced, there's really no reason to wait for next year.