BMW went a little mental with the 2017 7 Series. The new M760i xDrive is a 7 Series with serious guts under the hood, growing four additional cylinders and 156 more horsepower over the BMW 750 (see our review of the 2016). Powering the M760 is a 601-hp, twin-turbocharged V-12 that in our acceleration testing propelled the M760 to sports-car-like speeds.

For all its horsepower, however, don't call the M760 an M7. Think of the M760 in the same way you would a BMW M235i, which is performance-oriented but not as track-focused as the BMW M2. The M760 isn't an M7, and I think that makes it better suited to be a 7 Series.

Zero-to-60 in 3.5 Seconds

The 601-hp, twin-turbocharged 6.6-liter V-12 moves the 5,128-pound behemoth at a speed that would make Newton himself rethink his silly laws. This is the first V-12 used in the redesigned 7 Series. Though its turbochargers are mono-scroll — versus the twin-scroll used in smaller-displacement BMW engines — boost response is finger-snapping quick. The M760 is deceivingly fast thanks to a whisper-quiet engine that pours on power without a lick of strain.

The secret to putting 601 hp to the ground without massive wheelspin is the M760i's standard all-wheel drive (denoted by xDrive in the luxury sedan's name), which has a default rear bias to drive more like a rear-wheel-drive car. All-wheel drive, paired with launch control, helped the M760i reach 60 mph in 3.5 seconds in our testing and complete the quarter-mile in 11.4 seconds at 122.7 mph. Watch a video of the testing here.

Launch control with the eight-speed automatic transmission is the key. To engage it you, first switch off traction control, then it's as simple as flipping the M760i into its Sport driving mode, holding the brake, mashing the accelerator pedal until the engine revs to around 3,000 rpm, and letting off the brake while remaining full-bore on the accelerator. The M760i squeals its tires just a tad leaving the line, then rockets to 60 mph, continuing full steam through the quarter-mile at 120-plus mph.

The M760 is deceivingly fast thanks to a whisper-quiet engine that pours on power without a lick of strain.

Fast four-doors are not uncommon in the realm of $130,000-plus super sedans like the M760i; it starts at $156,495 including destination charge and a $1,700 gas-guzzler tax. The Mercedes-Benz AMG S 63, Porsche Panamera Turbo and Tesla Model S P100D could all either give the M760i a run for its money or blow its doors off (in the case of the 2.5-seconds-to-60-mph P100D). Compare the M760's specifications with its competitors' here. There's a new, faster AMG S63 for 2018, which you can read more about here.

The speeds recorded in the M760i are in a league with cars we've drag-strip-tested, including the 707-hp Dodge Challenger SRT Hellcat and 2017 Nissan GT-R. The 2017 Nissan GT-R hit 60 mph in 3.3 seconds and ran through the quarter-mile in 11.3 seconds at 121.7 mph, while the Challenger Hellcat was about 3.5 seconds to 60 mph and 11.3 seconds in the quarter-mile at 125.6 mph. Among four-doors, we ran as quickly as 11.0 seconds in the quarter-mile with the Charger SRT Hellcat.

Luxury First, Performance Second

It's an unnatural feeling to be going that fast in a car like the M760, partly because it remains a 7 Series first and a performance car second despite its rocket-ship acceleration. Like other 7 Series models, the M760 has the opulence of a bespoke luxury sedan, with rear lounging seats and some of the comfiest sofa-like front seats in its class. It also features signature 7 Series technology, including a removable rear tablet and a multimedia system with gesture control.

BMW hasn't uncorked the V-12's exhaust very much, so the M760i remains stately. There isn't a defining noise from the tailpipes; it's more of a whirl of mechanical noises than a distinctive or pleasurable engine song. The engine is quiet — almost too quiet for a performance car, though it's great for a luxury car.

All M760s come with four-wheel steering and an air suspension. The suspension is retuned for dynamic duty in the M760, and sticky Michelin Pilot Super Sport tires roll on M760-unique 20-inch wheels. The suspension tuning and tire choice are barely noticeable changes. Trust me, the M760 goes around bends quicker than it needs to, but it's mechanical grip over which you don't necessarily feel in control. That's due to light steering and body motion that rolls over at first turn-in, unlike the tuned, precise experience from an Audi RS 7 or Porsche Panamera. The M760's cushy ride is the one I'd take on a grand tour, however.

Who Really Needs One of These?

While testing the M760, I routinely fielded the question, "Who would ever buy one of these?" I admit that halfway through defending our $179,595-as-tested luxury sedan I might have sounded like a lunatic. But I hold my ground. The answer is no one "needs" a 601-hp 7 Series, but the 7 Series has been a favorite of ours since its 2016 redesign, and the M760 is my favorite variant of the already stellar sedan. The M760 is fast, but the core 7 Series experience hasn't been twisted into a spine-shattering performance sedan. If you want to buy one, though, it might be a special-order item, as Cars.com's national inventory doesn't currently show any available.