Zipping through a narrow canyon course etched into walls of granite, a street-legal rally car flows with the twisties on the Ortega Highway, California 74, which runs across the Santa Ana Mountains from the Pacific Coast at San Juan Capistrano to Lake Elsinore.

Actually, we're flying through this convoluted course, working the sporty Momo steering wheel and plying a Prodrive six-speed gearbox with the turbo-charged and inter-cooled engine whining and Potenza rubber wailing, all simply to see just what this thing can do.

And it can do a lot.

We're talking pin-your-ears-to-the-seat accelerations and king-of-the-street speeds in a relatively lightweight four-door package patterned after World Rally Championship (WRC) race cars.

This turbo-charged sports sedan from Japanese automaker Subaru is called the Impreza WRX STi.

It's based on the subcompact Impreza platform and derived from Subaru's WRX performance car but with more juice from a larger engine and more sporty paraphernalia to cede no street race from "The Fast and the Furious" crowd.

Those STi initials on souped up WRX signify Subaru Technica International, the motorsports division of Subaru and the force behind Subaru's trophy-collecting rally cars.

What's a rally car?

It's a race car usually of small scale with some stock equipment aboard but also a high-output engine and modifications for added safety like a protective roll cage and five-point racing harnesses for the two front seats.

Rally races pit a driver and co-pilot/navigator in a special race car against a stopwatch and detailed route maps, with daredevil competitors tearing across treacherous roads through cities and countryside, each vying to nail all checkpoints on time and beat the clock across a finish line.

Beyond North America in countries around the world, automobile rally racing receives the kind of sports attention that football fans in the United States reserve for contests like the Super Bowl. And in the WRC Subaru has racked up multiple wins, thanks to the wily nature of Subaru rally cars spinning off the Impreza platform.

The new 2004 WRX STi, also using the Impreza as its foundation, emulates those Subaru rally cars, only without roll bars and five-point safety belts.

In fact, Subaru's current WRX rally race car is based on the production model WRX.

Differences between street car and rally racer concern special modifications to the engine plus the addition of heavy-duty and adjustable suspension components, special seam welding of the structure to endure harsh punishment on a rally course, and the rally roll cage. (CONTINUE...)