Everybody loves a great superhero story -- you know, the protagonist hides his exciting, powerful and heroic character behind his alter ego's ordinary, average life. In the world of performance cars, this type of Superman/Clark Kent dichotomy has been sought for hiding pulse-quickening action behind everyday comfort and convenience.

German cars in particular seem to have succeeded in this split personality approach, and the 2009 BMW M6 remains one of these archetypal superheroes. Underneath the sheet metal and luxurious leather cabin lie heroic powers and abilities that can be summoned at will. For the uninitiated, the M6 appears much like a typical BMW 6 Series, with a long sweeping hood and sculpted bodywork stretched taut from nose to tail. Only the obligatory M badging and quad exhaust pipes hint at the M6's hidden potential.

What lies beneath is an inspiring 5.0-liter V10 capable of unleashing 500 horsepower with a stab at the accelerator. Accompanying the "up, up and away" of the celebrated engine is an operatic wail that can only be sung by a harmonious chorus of 10 cylinders. This heart beats deep within an athletic frame that can give nearly any foe a run for its money. The sporty suspension keeps the M6 flying flat through the most demanding of curves, while the seven-speed sequential transmission executes gearchanges with supreme immediacy. Meanwhile, our superhero M6 can transform back into the unassuming highway cruiser or daily commuter at a moment's notice.

But like all superheroes, the M6 has unexpected weaknesses that can be exploited by competitors. These shortcomings include the SMG's tendency for herky-jerky shifting in automatic mode during heavy traffic, the disappointing lack of steering feel for a BMW and the annoyingly complex nature of BMW's iDrive control system found on the early production 2009 M6. Later production cars feature an all-new iDrive that features menu buttons for frequently used functions (stereo, navigation, telephone) adjacent to the control knob. We strongly suggest waiting to get one of these cars.

However, none of this is enough to bring our hero to an unceremonious end. Few rivals can keep pace with a 2009 BMW M6, especially when price is considered. For about $100,000, you might consider a Porsche 911, a Jaguar XKR, a Maserati GranTurismo or a Mercedes-Benz CL550. All are highly desirable, of course, but the BMW stands tall in terms of maximum performance. The M6 is even capable of going toe to toe against higher-priced coupes from AMG, Bentley and Aston Martin. With this in mind, we think the superhero M6 is worthy of consideration among luxury- and performance-focused cars.

The 2009 BMW M6 is offered in either coupe or convertible body style. As a hopped-up version of BMW's 6 Series, the M6 benefits from (in addition to the V10 engine and more sporting suspension tuning) 19-inch double-spoke wheels, a carbon-fiber roof (coupe only) and a body kit with an aggressive front airdam, side sill extensions and a rear diffuser.

Other standard features include adaptive xenon headlights, adjustable suspension dampers, leather-upholstered 12-way power front sport seats, driver memory settings, dual-zone automatic climate control, heated front seats, Bluetooth, a navigation system with real-time traffic updates, and a 13-speaker Harman Kardon surround-sound audio system. The convertible comes with a fully lined power soft top.

Among the handful of options are a head-up display, keyless ignition and entry, satellite radio, HD Radio, iPod/USB integration and extended leather added to the dash and console. Walnut wood trim is standard in the M6, but olive ash wood and carbon-fiber trim are also available.

The 2009 BMW M6 is powered by a 5.0-liter V10 that blasts out a whopping 500 hp and 383 pound-feet of torque. Power goes to the rear wheels through a standard seven-speed automated manual gearbox that can be operated as a traditional automatic or as a manual via wheel-mounted paddles or a console-mounted shifter. A six-speed manual transmission is also available at no additional cost.

The M6 accelerates with mind-bending quickness, providing the easily spun tires aren't lit up in a cloud of white smoke. In testing, the SMG-equipped coupe reached 60 mph in only 4.6 seconds and cleared the quarter-mile in 12.8 seconds. Acceleration numbers for the heavier convertible M6 are only a few 10ths slower. EPA-estimated fuel economy comes in at 11 mpg city/17 mpg highway and 13 mpg in combined driving.

As with most new BMWs, the 2009 M6 comes equipped with a barrage of safety equipment that includes stability control, traction control, antilock disc brakes, front-seat side airbags, side curtain airbags for the coupe, a rollover protection system for the convertible and front and rear parking sensors. A high-performance "M" driving mode relinquishes control of some of the electronic aids to allow expert drivers more leeway.

Pin the throttle pedal of a 2009 BMW M6 to the floor, and you are likewise pinned to the seat, thanks to the quick-revving V10. In manual mode, the SMG provides lightning-quick upshifts and perfect rev-matched downshifts. Unfortunately, in automatic mode the transmission is decidedly lackluster, with herky-jerky responses in low-speed traffic conditions. Opting for the six-speed manual transmission would seem to be an ideal solution, though in testing of a similarly equipped M5, we found the manual was prone to overheating.

Despite the car's size, the M6 is a willing companion on tight, twisty back roads. Switching the "DSC" stability control off completely disables the system, allowing talented pilots to deftly drift the M6 through curves with confidence, though many drivers will desire more feedback and feel from the steering. Even so, the M6 is surprisingly easy to live with as a daily driver. The able and adjustable suspension skillfully isolates passengers from road imperfections, making for a comfortable road trip or commute.

The dash and console of the 2009 BMW M6 feature a clean, simple design and layout, with wood trim and climate controls that are easily operated. While BMW's much-maligned iDrive multifunction controller may be counterintuitive for many, we suggest looking for one of the later production units that feature the all-new, more user-friendly iDrive. Not only does it make selecting a radio station easier, but it provides access to more in-depth functions like the maximum-performance "P500 Sport" mode that unleashes all 500 hp with near-telepathic throttle response.

The M6's front sport seats effectively hold the driver and passenger in place during the most daring of cornering maneuvers, thanks to their aggressive side bolstering. The wide range of seat adjustments in combination with a tilt and telescoping wheel ensures a comfortable driving position for any body size or type. The rear seats are cramped, but they're suitable for short trips. Trunk capacity for the coupe is 13 cubic feet, while the convertible manages a decent 12.4 cubes (10.6 with the top down).