Subaru unleashes the limited edition STI S209 in Detroit

As an S-line product, the STI S209 encompasses upgrades in power, handling, aerodynamics and driver engagement, and undergoes final assembly in Kiryu, Japan, where it receives engine modifications and bodywork alterations that in total require it to be homologated for the American market by STI; thus, the S209 is considered the first 'STI-built' Subaru sold in America.

The S209 carries on a high-performance tradition that dates to STI-built models that were exclusive to the Japanese domestic market - the 2000 S201 through the 2018 S208.

Designed with a focus on high-performance driving, the S209 draws inspiration and tech transfer from STI's most formidable track machine - the WRX STI Nurburgring Challenge race car, which won the SP3T class at the 2018 24 Hours of Nurburgring, marking the fifth time STI dominated the SP3T class at the gruelling endurance race.

The S209, like the Nurburgring Challenge race car, wears an expanded wide-body exterior treatment, which extends the vehicle's overall width to 72.4 inches, or 1.7 inches wider than a standard WRX STI. The bulging fenders accommodate wider front/rear tracks and 265/35 Dunlop SP Sport Maxx GT600A summer-only tyres wrapped around lightweight 19-inch forged BBS alloy wheels.

The all new tyres, developed exclusively for the S209 by Dunlop, are a significant contributor to the car's tenacious maximum lateral grip of over 1g. Vents on the front fenders provide additional engine cooling, while vents on the rear fenders rectify air turbulence to reduce drag.

Brembo brakes, with cross-drilled steel rotors and six-piston monoblock front calipers and two-piston monoblock rear calipers, provide stout stopping force, thanks in part to upgraded high-friction pads that deliver improved fade-resistance.

Underneath the S209's broader body are specially developed Bilstein dampers, stiffened coil springs, a 20mm rear stabiliser bar and pillow-type bushings for the front/rear lateral links.

The S209 incorporates reinforcements to the front crossmember and rear subframes and, a la the Nurburgring race car, a flexible front-strut tower bar and flexible front/rear draw stiffeners.

The draw stiffeners apply tension between the body and cross member to optimise chassis flex, improving stability when cornering and delivering better ride, handling and steering response. Other Nurburgring race car tech that trickles down to the S209 include front, rear and side under spoilers; front bumper canards; and carbon fibre roof panel and rear wing.

A thoroughly reworked version of the legendary EJ25 2.5-litre turbocharged Boxer engine propels the S209. Featuring an STI turbocharger manufactured by HKS, the EJ25 serves up an estimated 336bhp, thanks in part to a larger turbine and compressor (up 6% and 8% respectively, compared to WRX STI) as well as maximum boost pressure that has been increased to 18psi (16.2psi for WRX STI).

Proudly displaying an S209 serial number plate, the enhanced Boxer engine utilises forged pistons and connecting rods that are both lighter and stronger. Mid-range torque, too, gets a notable bump, up 10% at 3,600rpm, delivering higher corner exit speeds when driving on track.

For ultimate driver engagement, the S209 comes exclusively with a close-ratio six-speed manual transmission that routes power to a full-time all-wheel drive system with limited-slip differentials, a driver controlled centre differential, active torque vectoring and multi-mode vehicle dynamics control.

A recalibrated SI-Drive system offers three modes: Intelligent for improved fuel economy and smoother power control; Sport for optimised power balance between response and control; and Sport Sharp for achieving the best acceleration times. STI engineers recommend Sport over Sport Sharp for circuit driving, as the less aggressive throttle map allows for greater driver control.