(FORTUNE Magazine) – Some advice to innocent drivers worldwide: Be very, very afraid. Porsche, the platinum standard of sports cars, has just done something frightening. It has made its latest fire-breathing flagship, the 911 Turbo, accessible--in driveability if not affordability--to the average lane-hogging, road-weaving Joe. Heck, it's so smooth and easy to drive, your grandmother could handle it. And although plenty of commuters won't be able to cough up the necessary $111,000, that still leaves way too many overpaid bad drivers who can. (If only driving skill came attached to those inflated dot-com options...)

When Porsche invited me to southern Spain to test the new Turbo, however, I wasn't sure if the attempt to make a well-behaved 420-horsepower super-sports car would work. After all, the current base 911 is too soft and Lexus-like for my taste, despite its technical prowess. Could the old, fear-inducing magic of the past four generations of Turbos be resurrected?

By the time I am handed the key to the Speed Yellow Turbo parked on the cobblestones outside the historic parador, my worries begin to fade. Inside it's all business: The fine-grain leather is there to hold you in place, not swaddle you in luxury--distracting bells and whistles need not apply. With one twist, the rough-sounding six-cylinder sparks to life, and my pulse jumps with it. I ease the gearshift into first without any struggle (for the first time, a clutchless Tiptronic automatic transmission is also available), the clutch gliding painlessly under my left foot.

Out on Spain's empty twisties, I quickly realize that the Turbo is in fact Sybil. At low rpms, the car remains chivalrous. Above 4,000 rpm, however, its inner rebel is released. Gunning through an unexpectedly slippery traffic circle too fast, I feel the tail swish. But before I can even react, the electronic stability control kicks in--not by slowing me down, but by strong-arming the Turbo's tush back into line a heck of a lot more competently than I could.

"Do you have any complaints with the car?" asks Porsche engineer Peter Guzmer as I pull into the parking lot of our quaint lunch stop. I note with disgust the small smile of certainty that creeps up at the corners of his mouth. He knows in his heart that I can't have many.

It's not that I don't want to like Porsche's latest monster, it's just that as a journalist I pride myself on finding flaws with nearly everything. Dredging up a weak-kneed whine about the Turbo's shiny plastic control buttons and a too-user-friendly gearbox makes me feel as if I'm not doing the proper scrutinizing. (Plus, Guzmer tells me the buttons are already being changed.) But the truth is, I conclude after another day and a half of Spaniard-scaring fun, that Porsche has done it again: The company has engineered a best-of-show performer. It doesn't have the head-snapping good looks of its competitors--the $160,000 Ferrari 360 Modena and the $130,000 BMW Z8, for instance--but with the extra dough you can put yourself through a professional driving school.

And you'll want the practice. Although Porsche has softened the notorious bite of this four-wheel-driver, it still packs a g-laden response to hard acceleration, braking, cornering, or any other maneuver you'd care to try. And that, at the end of the day, is the only real flaw in the new Turbo. It's so competent that its limits are as far out of sight as the valuations of tech stocks these days. In other words, beware the crash.

--SUE ZESIGER