One of the byproducts of the horizontally opposed engine is the tangled turbo system. With exhaust ports on opposite sides of the engine, and only one turbo to feed, the exhaust manifold must snake around to merge into one point. Subaru's design has been to place the turbocharger behind the engine and utilize a short plumbing top-mount intercooler. But, to resist heat soak in high power applications, a tiny intercooler placed right on top of the engine is not the best idea.
Blitz uses their front-mount LM Intercooler kit on this Spec C, and the multiple tubes under the hood are a dead giveaway. Also helping keep the car cool is a Blitz Racing LM Radiator and a higher-pressure radiator cap. With a set of Blitz Racing spark plugs installed, the Spec C's engine tuning was considered finished. Blasting out of a Blitz Nur-Spec C-Ti exhaust system, the Subaru was tuned with a Blitz R-FIT fuel controller, Blitz SBC i-Color boost controller and Blitz A/F Ratio Analyser. The final output is now a solid 358.3 hp at 6190 rpm and 330.5 lb-ft at 5150 rpm.
Even with the increased power levels, the entire drivetrain remains stock, down to the clutch and shifter. However, upgrades have been made in the interest of track readiness. The stock Brembo four-piston front and two-piston rear fixed caliper setup has been praised over and over for its stopping power and firm modulation. Blitz has increased the bite and temperature range of this STi's system with the addition of Blitz Pagid RS4-2 front and Blitz MR-3 rear brake pads. Providing the pavement stick is a set of Dunlop Direzza Sport Z1 tires, sized 245/40/18 all around. The already capable Spec C suspension has been dumped in favor of prototype Blitz Damper ZR coilovers, fit with a stiff 12 kg/mm front and 8 kg/mm rear spring rate. The Blitz coilovers feature full dampening adjustment, ride height adjustment and front upper camber plates
To those who aren't in the know, the STi appears every bit like the stereotypical street racer machine with its collection of wings and scoops. But Subaru's STi is no fake. Homologated for Group N rally use, the STi Spec C features an intercooler-feeding hood scoop, sculpted side skirts, front undertray, rear diffuser, roof scoop and box wing. Blitz's only addition is the Flex front spoiler, color matched to the STi's factory white.
Keeping true to Subaru's original recipe, Blitz has tuned the new 2006 Impreza WRX STi Spec C according to design. No stereos, no fiberglass and no unnecessary junk. Just a tightening of all the bolts and a double dose of extra power and speed. Every car should be so lucky.