The 2007 Volkswagen GTI R Concept starts with Volkswagen’s 2.0-liter FSI turbocharged four-cylinder powerplant, an award-winner for its unique combination of direct injection & turbocharging. APR also replaced the turbocharger with a larger Garrett ball-bearing unit with twice the flow capacity & pumped up the boost to 21 pounds per square inch. All of the pressure-side plumbing was strengthened with silicon hose. A large-diameter cast-aluminum, black powder-coated intake pipe feeds the big turbo the cool air it needs from the larger, front-mounted intercooler, delivering twice the stock air flow. An Inconel exhaust manifold & an APR stainless steel exhaust system ensure efficient flow-through. It’s a tidy, factory-like transformation, & the result is a whopping 375 horsepower, on 93 octane pump gas. If 100-octane race fuel is used, output rises to some 400 horsepower.