Most BMWs have a businesslike demeanor. Like a high-powered corporate executive, they're excruciatingly quick-witted, measured in their movements and speech, and somehow always at the top of their game when competitors come knocking. However, the 2007 BMW M6 takes that archetypal Bimmer personality and twists it into a demented hooliganism. It's not just that it's the quickest car in the BMW lineup or that this coupe and convertible duo will keep pace with all sorts of Italian exotica. It's the suffocating clouds of tire smoke the V10-powered M6 leaves in its midst as driver and passenger bask in its top-grade leather interior. At the $100K mark, few cars approach this level of decadence.

Short for "Motorsport," the M versions of BMW's fine machines provide increased performance by way of their high-output engines and sport-tuned suspensions. Subtle body tweaks along with special wheels and sport seats add to the M allure. The M6, as you might guess, is the high-performance version of BMW's 6 Series. The first one debuted in 1987 sporting an inline-6 modified to put out 256 horsepower -- an impressive output for that time, especially for a six-cylinder engine that didn't utilize turbocharging or supercharging.

Introduced last year in coupe form, the current BMW M6 possesses the same high-performance GT spirit but is considerably more powerful and capable. Sharing its underpinnings with the current M5 super sport sedan, the M6 offers the same F1 wail from the engine compartment, thanks to a 5.0-liter all-aluminum V10 capable of 500 hp at an amazing 7,750 rpm and 383 pound-feet of torque at 6,100 rpm. BMW's clutch-pedal-less Sequential Manual Gearbox (SMG) routes all that to the rear wheels, and because the coupe weighs 100 pounds less than the sedan (thanks to weight-saving measures like a carbon-fiber roof panel), it's even quicker to 60 mph. For 2007, the BMW M6 Convertible debuts. It packs on almost 500 pounds but provides a whole new way to enjoy the V10. With nothing between you and the harmonious bellow of one of the most remarkable engines in production car history, the only thing to do is slather on SPF 50 and let the sun, wind and sound prickle your senses.

Of course, there's a lot more to the M6 coupe and convertible than straight-line speed. An electronically adjustable suspension, a 50/50 weight balance between the front and rear axles and BMW's trademark ultra-communicative steering make the M6 a willing partner on empty back roads. With its adaptive suspension set to "Comfort" mode, the M6 also functions perfectly well as a daily driver.

In the high-performance coupe and convertible market, few of the players offer this kind of versatility. For instance, the Porsche 911 Turbo and GT3 are superior performers whether you're talking acceleration or handling, but you give up plenty in the way of comfort and rear-seat accommodations. Same goes for exotics like the Ferrari F430, Lamborghini Gallardo and Aston Martin DB9, and they cost almost twice as much. Aston's V8 Vantage, Jaguar's XKR and Maserati's GranSport come closer to the BMW's price tag (the Jag is several grand cheaper, in fact), but they just aren't as quick. For equivalent luxury and comfort, you'd have to look at the Mercedes-Benz SL55 and Bentley Continental GT/GTC, and those cars command higher prices as well. Much higher in the case of the Bentley. On the whole, then, the 2007 BMW M6 is an incredible value -- for that rare breed of buyer in need of a true four-seater that also delivers staggering performance and opulence.

The 2007 BMW M6 lineup consists of a high-performance midsize coupe and convertible, both of which have seating for four. Tasteful M-specific equipment like 19-inch double-spoke wheels (wearing 255/40 front and 285/35 rear performance tires), a carbon-fiber roof (coupe only) and a body kit with an aggressive front airdam, side sill extensions and a rear diffuser set the M6 apart from the 650i in your neighbor's driveway. The cockpit features leather-upholstered sport seats with 12-way power adjustments (14-way for the M6 Convertible) and a fat-rimmed M sport steering wheel. Of course, all the expected luxury features are standard, including adaptive xenon headlights, a navigation system with real-time traffic updates, dual-zone automatic climate control, a 13-speaker Harman Kardon Logic 7 audio system, Bluetooth wireless capability, one-touch power windows and seat heaters. Among the handful of options are a head-up display, keyless startup, Sirius Satellite Radio, high-definition (HD) AM/FM radio and a full leather interior (which adds animal hide to the dash and console). Walnut wood trim is standard in the M6, but olive ash wood and carbon-fiber trim are also available. You also have your choice of red, brown, beige, gray or black leather upholstery.

A 5.0-liter V10 powerhouse is found under the hood of every BMW M6. Peak output stands at 500 hp and 383 lb-ft of torque. With BMW's latest technology, such as infinitely variable valve timing and a separate throttle butterfly for each cylinder, the V10 has a broad spread of power that grows even more insistent as it rushes toward its 8,250-rpm redline. The sole transmission offering is a seven-speed automatic Sequential Manual Gearbox (SMG). When shifted manually (via the paddles behind the wheel or the console-mounted shifter), the third-generation SMG works wonderfully, blipping the throttle expertly before blindingly fast downshifts and upshifting with rapidity that will win most stoplight races. In automatic mode, however, the SMG is considerably less satisfying, as its responses can be unpredictable and sluggish in low-speed traffic situations. Fortunately, the iDrive system has an MDrive menu that allows the driver to program preferred throttle and transmission settings.

We've timed the M6 coupe at just 4.6 seconds for zero to 60 mph, while the quarter-mile came up in just 12.8 seconds at 117.4 mph -- a successful launch requires delicate footwork, given the massive amount of torque going to the 285/35ZR19 rear tires. BMW says the M6 convertible is only a few 10ths slower. Top speed is electronically limited to 155 mph on both cars.

Standard safety features on the 2007 BMW M6 include stability control (which features a high-performance "M" mode that gives the expert driver more leeway), traction control, antilock brakes, front-seat side airbags, side curtain airbags (coupe only), a rollover protection system (convertible only) and front and rear parking sensors.

Hammer the throttle in a 2007 BMW M6 and, because the singing V10 revs so freely and quickly, the SMG makes its electrohydraulic shifts verrry quickly. Yet straight-line acceleration is but one facet of the BMW M6's sporting personality. When you switch off the stability control (dubbed "DSC"), it's completely off. Thusly configured, a skilled driver can drift the finely balanced M6 with aplomb, as the responsive steering lets you know exactly what's going on under the front tires when you're hustling the big coupe (or convertible) along. Yet all this performance potential doesn't mean the M6 is hard to live with on a day-to-day basis: The high-performance Bimmer's well-sorted and adjustable suspension keeps the car flat through the corners while also providing enough ride comfort for long road trips and the weekday grind.

An uncluttered dash and console feature simple climate controls and handsome wood trim. Yes, there is iDrive, BMW's multifunction controller, and although we find it frustrating to use, it's worth the effort to get acquainted with it in the M6: The coveted "P500 Sport" mode, which gives you access to all 500 hp and maximum throttle responsiveness is only accessible via the iDrive system's MDrive menu. Multi-adjustable sport seats feature aggressive side bolsters to hold driver and passenger in place during spirited runs through the corners and, along with a power tilt-and-telescope steering wheel, allow drivers of all sizes to get comfortable in the cockpit. Although the two rear seats don't offer a lot in the way of legroom for adult occupants, they're certainly usable on short trips. Trunk capacity is 13.0 cubic feet in the coupe and a still healthy 12.4 in the convertible (10.6 with the top down).