Subaru Impreza WRX STI Version 6 (GC8)
The WRX STI Version 6 continued the GC8 platform's development, building on the improvements of each preceding version. Released in late 1999 for the Japanese domestic market, it represented the final refinement of what many consider the purest STI formula.
The EJ20 turbocharged flat-four remained at the heart of the car, producing the customary 280 PS at 6,500 rpm with 363 Nm of torque at 4,000 rpm. The IHI turbocharger was refined for improved response, and the intercooler efficiency was enhanced. The engine retained its characterful flat-four rumble and its eagerness to rev, though the power delivery was smoother and more progressive than earlier versions.
The DCCD (Driver Controlled Centre Differential) was now a standard feature, allowing six positions from fully locked to open. This gave the driver unprecedented control over the car's cornering behavior. Combined with front and rear limited-slip differentials, the STI's traction was extraordinary in all conditions.
The suspension received the latest Bilstein inverted monotube dampers with revised valving. Spring rates were optimized based on feedback from the World Rally Championship program, and the anti-roll bar rates were adjusted for improved balance. The quick-ratio rack-and-pinion steering provided excellent feel and response.
The braking system featured four-piston Brembo calipers at the front gripping ventilated discs, with two-piston calipers at the rear. This provided stopping power that matched the car's significant straight-line performance.
The Version 6 received cosmetic updates including revised headlights, a new front bumper design, and updated interior trim. The signature rear wing, gold wheels, and 555 Blue color scheme remained as visual identifiers of the STI.
The GC8 STI Version 6 sits at the sweet spot of the STI lineage — mature enough to incorporate all the lessons learned from five previous versions and WRC competition, yet still possessing the raw, involving character that would be progressively softened in later STI generations.
EJ20 engine health is paramount — compression and leakdown test mandatory. Check for ringland failure evidence. Turbo shaft play and boost control function. DCCD must operate across full range. Bilstein dampers should show no leaks. Rust in rear arches and sills. Stock, unmodified GC8 STIs are rare and increasingly valuable.
Produced at Subaru's Yajima factory in Gunma Prefecture, Japan. The Version 6 was released in late 1999 as part of the GC8 STI range. Production numbers for individual versions were not separately tracked.