Intro
The 1999 Subaru Impreza WRX STI represents a pivotal moment in Japanese automotive history, emerging from Subaru’s dominant rally racing program of the 1990s. This model year specifically marked the evolution of the first-generation STI into its more refined GC8 chassis, incorporating technology directly derived from World Rally Championship competition.
In JDM culture, the ’99 STI stands as an icon of attainable performance. While Italian exotics remained financially out of reach for most enthusiasts, the STI delivered supercar-challenging acceleration and all-weather capability at a fraction of the price. Its distinctive boxer rumble, signature blue and gold color scheme, and practical four-door configuration made it both aspirational and functional—cementing its status in Japanese performance car heritage alongside the Skyline GT-R and Lancer Evolution.
This particular build showcases the enduring appeal of the GC8 platform. Unlike heavily modified examples that have lost their period-correct charm, this STI balances thoughtful modern upgrades with a preservation of the original engineering that made these vehicles special. The tasteful modifications enhance rather than overshadow Subaru’s rally-bred DNA, demonstrating why these first-generation STIs continue to appreciate in value and significance among collectors and enthusiasts alike.
Builder Profile
A third-generation Japanese-American mechanical engineer from Portland, Oregon, Takumi Hayashi developed his passion for JDM cars while spending summers with relatives in Gunma Prefecture, Japan. By day, he works at a motorsport components manufacturer, but evenings and weekends are dedicated to his meticulous approach to vehicle modification.
Hayashi’s tuning philosophy emphasizes the balance between power and control—”Restraint creates character,” as he often says. Rather than chasing outrageous horsepower numbers, he focuses on creating responsive, harmonious builds that excel on both mountain passes and track days.
Active in the Pacific Northwest rally scene since 2008, Takumi has built a reputation for his technical expertise and willingness to mentor newcomers. His Impreza WRX STI represents seven years of gradual, purposeful evolution, with each modification carefully selected to complement the car’s original engineering ethos rather than overpower it.
Why We Love It
The 1999 Impreza WRX STI transcends mere transportation—it’s motorsport philosophy distilled into street-legal form. During a period when Japanese engineering reached its zenith, Subaru crafted a rally weapon with democratized accessibility.
Its EJ207 powerplant delivers power with a distinctive character unlike anything else—220kW through a mechanical symphony of flat-four burble and spooling IHI turbocharger. The shift in power at 4000rpm isn’t merely acceleration; it’s mechanical theater.
The GC8’s chassis communicates with exceptional clarity—unfiltered and direct. Each steering input transmits through the hydraulic rack with a mechanical honesty lost in modern drive-by-wire systems. Its raw, communicative nature stands as counterpoint to the digital isolation of contemporary performance cars.
This particular vintage represents the sweet spot in Subaru’s evolution—after the early experimental phase yet before homologation requirements were diluted. The direct rally-to-road development cycle created engineering solutions based on competition necessity rather than focus groups.
What truly elevates the ’99 STI is its uncompromising nature—titanium turbo components, hand-ported heads, and driver-selectable DCCD differential control reveal an engineering philosophy that prioritized performance over practical concessions.
Mods
ENGINE & DRIVETRAIN
- HKS GT3037S turbocharger kit
- APS front-mount intercooler
- HKS Hi-Power exhaust system
- GReddy blow-off valve
- Exedy racing clutch
- Trust/GReddy oil cooler
- Samco silicone hose kit
- Cusco transmission mount
- Cosworth head gasket
- STI 6-speed transmission (upgraded)
SUSPENSION & BRAKES
- TEIN Super Racing coilovers
- Cusco front and rear strut tower bars
- Whiteline adjustable sway bars
- AP Racing 6-piston front brake calipers
- Brembo 4-piston rear brake calipers
- Project μ brake pads
- Goodridge stainless steel brake lines
- Cusco lower arm bar
WHEELS & TIRES
- Volk Racing TE37 18×9.5″ +22 (bronze)
- Yokohama ADVAN Neova AD08R (265/35R18)
- Project KICS R40 lug nuts
- 20mm wheel spacers (rear)
EXTERIOR / AERO
- Prodrive rear wing
- STI Version 6 Type R front lip
- Chargespeed side skirts
- APR carbon fiber front splitter
- HID headlight conversion
- JDM yellow fog lights
- Varis rear diffuser
- PIAA super silicone wiper blades
INTERIOR
- Bride Zeta III bucket seats
- Takata 4-point harnesses
- Personal Neo Grinta 330mm steering wheel
- Works Bell quick release hub
- Nardi shift knob
- Defi Advance BF gauges (boost, oil pressure, water temp)
- STI JDM floor mats
- Cusco 6-point roll cage
ELECTRONICS / ECU
- APEX Power FC engine management
- HKS EVC boost controller
- Blitz SBC i-Color boost controller
- Pioneer DEH-P88RS CD head unit
- Alpine Type-R speakers
- JL Audio 10W6 subwoofer
- AEM wideband O2 sensor
- Innovate MTX-L Air/Fuel gauge
Driving Impression / Build Philosophy
The 1999 Impreza WRX STI’s modifications create a cohesive package where each component serves the overall vision of a street-legal time attack machine with exceptional daily drivability. The carefully selected power upgrades—from the Stage 2 ECU tune to the upgraded turbocharger—deliver linear power without the laggy, peaky delivery that plagued many modified turbocharged cars of this era.
The suspension modifications strike a delicate balance between performance and usability, with the Bilstein coilovers offering track-capable handling while maintaining enough compliance for street use. Chassis rigidity enhancements through the strut tower brace and undercarriage bracing create a more responsive platform that communicates road feedback without excessive harshness.
This build philosophy prioritizes functional performance over show-car aesthetics, though the subtle exterior modifications like the JDM front lip and lightweight Volk Racing wheels complement the car’s aggressive stance while serving aerodynamic and unsprung weight reduction purposes. The interior upgrades focus on driver engagement and feedback—Recaro seats hold the driver securely without sacrificing comfort during daily commutes.
What makes this build exceptional is its purposeful restraint; rather than chasing maximum power figures, each modification was selected to enhance the STI’s inherent strengths while addressing its few weaknesses. The result is a balanced package that excels in weekend time attack events while remaining practical enough for everyday use.
FAQ
How reliable is the 1999 Subaru Impreza WRX STI?
The 1999 WRX STI is generally reliable when properly maintained, with many examples exceeding 200,000 miles. Regular maintenance is essential, particularly oil changes every 3,000-5,000 miles and timing belt service at 105,000 miles. The EJ20 engine is robust when stock, but reliability decreases considerably with aggressive modifications or neglected maintenance.
What is the tuning potential of the Version 5 STI?
The 1999 STI’s EJ20 turbo engine responds exceptionally well to tuning. With basic bolt-on modifications (intake, exhaust, intercooler), power can be increased to 300-320hp. More aggressive builds with upgraded turbochargers, fuel systems, and forged internals can safely achieve 400-450hp, while fully built engines can handle 500+hp with professional tuning.
What are the most common issues with the 1999 STI?
Common issues include piston ring failure causing oil consumption, head gasket leaks (though less prevalent than non-turbo models), turbocharger failure around 100,000 miles, and valve cover gasket leaks. Transmission synchros can wear prematurely, especially in 2nd gear. Rust is also common around rear quarter panels and wheel arches on examples from salt-belt regions.
Which modifications offer the best performance gains?
The most effective modifications include a turbo-back exhaust system, front-mount intercooler upgrade, electronic boost controller, and a professional ECU tune. These provide considerable power gains while maintaining reliability. For handling, coilovers, stiffer sway bars, and chassis bracing deliver the most noticeable improvements in cornering performance.
How expensive is it to maintain a 1999 STI?
Ownership costs are higher than average compact cars. Expect to spend $1,500-2,500 annually on maintenance for a well-kept example. Parts are increasingly difficult to source, especially JDM-specific components. Premium fuel is required, and oil consumption can be high (0.5-1 quart per 1,000 miles is not uncommon). Insurance rates are also typically higher due to the performance classification.
Are import restrictions an issue for the 1999 STI in North America?
Since the 1999 STI wasn’t officially sold in North America, all examples are imports. Vehicles must comply with the 25-year import rule in the US (now legal) or the 15-year rule in Canada. Proper importation documentation is essential for registration. Some states have stricter emissions requirements that may present challenges for registration.
What distinguishes the 1999 (Version 5) STI from other years?
The Version 5 STI features the distinctive two-door coupe body style with wide fenders, unique fog light covers, and specific STI badging. It produced 280hp from its EJ20 engine with a twin-scroll turbocharger. This generation is known for its balanced driving dynamics, iconic rally heritage, and the driver-controlled center differential (DCCD) system that wasn’t available on standard WRX models.
Conclusion
The 1999 Subaru Impreza WRX STI stands as a pivotal milestone in automotive history, bridging past and present with its enduring impact. While modern sports cars boast sophisticated electronics and refinement, the raw, mechanical connection offered by the ’99 STI provides an increasingly rare driving experience that continues to captivate enthusiasts decades after its release.
Its influence extends far beyond its production years, establishing a performance blueprint that subsequent generations have built upon. The STI’s rally-bred technology—symmetrical AWD, turbocharged boxer engine, and driver-focused ethos—remains central to Subaru’s performance identity today.
Within JDM culture, the ’99 STI represents automotive purity at its finest—a vehicle designed without compromise, where function dictated form. Its distinctive hood scoop, aggressive stance, and signature World Rally Blue paint have become iconic symbols within enthusiast circles. The car’s presence at meets and shows inevitably draws crowds, with appreciation crossing generational boundaries.
What truly cements the ’99 STI’s legacy is its accessibility as an attainable dream car. Unlike many performance icons whose values have skyrocketed beyond reach, the STI remains—while certainly appreciating—within grasp for dedicated enthusiasts, offering world-class performance and cultural significance without exotic pricing.
In an era of automotive homogenization, the 1999 STI’s character-filled driving experience, distinctive aesthetics, and competition heritage guarantee it will remain a benchmark for enthusiasts seeking automotive authenticity for decades to come.