After teasing the Internet with a poorly-worded Twitter announcement earlier in the week, Tesla Motors CEO Elon Musk this evening unveiled a new optional powertrain configuration for the entire line of the company's flagship Model S sedans: dual motors, powering all four wheels.

After making a few good-natured jokes about how he recently received a crash-course in the colloquial meaning of "the D," Musk kicked off the event by having a factory robot hoist an all-wheel drive Model S frame up from beneath the stage. USA Today jumped the gun with their announcement summary, and the report proved accurate. All-wheel drive will be an available option on all Model S trim levels and the new top-end P85D version will have a 0-60 time of 3.2 seconds. It will also feature a small increase in range, to 275 miles, over its rear-wheel drive predecessor.

Standard Model S sedans have until now all featured a single rear motor slung between and slightly behind the car’s rear axle, powering the rear wheels only; the new "D" models will add a second motor between the two front wheels. The new models will have a "D" suffix added to their model, so the entry-level Model S with the 60 kWh battery and all-wheel drive would be the "60D," and the top-end P85 performance model would become the "P85D."

The addition of a second motor to the mix obviously gives the cars surer footing in the wet and on ice. This is a big asset considering the accelerated sales rates of Tesla vehicles in northerly climates—like Norway, where Model S buyers get an enormous tax break for purchasing the electric car. The extra motor benefits the car in other ways besides simply giving all-wheel-drive stability, too: the top-end P85D is faster than even the P85 performance model, too—according to Tesla, the P85D turns in 0-60 mph times of 3.2 seconds, shaving a full second off of the P85+ model’s 0-60 time. Musk said the addition of the second motor will give the D models "half again" as much power as the rear-wheel drive versions. According to Musk, the high performance models will have three driving modes available to choose from: "normal," "sport," and "insane."

A second motor means more power consumption, too, but Musk said that the efficiencies designed into the new drivetrain actually yields an increase in range rather than a decrease. The car will dynamically shift power between the front and rear drive wheels, which Musk says allows the car to propel itself forward with the maximum amount of efficiency for any given speed. The maximum EPA-rated range of the rear-wheel drive 85 kWh models is 265 miles, but the all-wheel drive D variant ekes out an additional 10 miles of range. Based on our hundreds of miles of hands-on time with a Model S last October, we can say that spirited driving can drastically reduce that maximum range number—and adding a second motor and even more acceleration into the mix will almost certainly invite a heavier foot on the accelerator pedal.

But a second motor wasn't all that Musk announced this evening—semi-automous driving enhancements are also on the menu. Musk says that they have "accelerated autopilot," and that all Model S cars produced within the past two weeks has the necessary hardware to support the new "autopilot" features. This hardware includes forward-looking radar, image-recognition cameras, and 360-degree ultrasonic sonar. All these gizmos will give the Model S the ability to read speed limit signs and cruise at whatever the road's limit happens to be, along with the ability to automatically change lanes when a driver indicates with the car's turn signal. The updated autopilot package will also include standard driver assistance tools like lane departure warnings, adaptive cruise control, and automated braking.

Musk also said that the updated autopilot technology will allow the Model S to self-park, parallel parking by itself or even pulling itself automatically into your garage. He also teased that on "private property" (or at least not on public roads), an autopilot-equipped Model S would even be able to pull out of a garage and navigate to where you're waiting for it to pick you up—evoking images of Michael Keaton's Batmobile. You could even, Musk explained, program it to meet you at your doorstep at a certain time every day with the AC running and your favorite music already queued up to play.

The new autopilot functions bring with it a new interface, with the dashboard's central display ditching the round speedometer wheel and instead showing the car's speed and indications of what the sensors are detecting around the vehicle (other cars, obstacles, and so on). The car's electromechanical steering will actively resist being steered into other objects, too. Musk said that the force can be overcome if you try, but the car will push against the driver trying to send it into a collision.

Just last week, Musk told CNN in an interview that he wanted Tesla cars to be "90 percent" self-driving by the end of next year; these automation features help put the company’s products on course to hit that goal. Between the cars’ inbuilt GPS positional awareness and the new features, the majority of the tools necessary for self-driving would now in place. Musk said that the vehicles aren't yet capable of fully autonomous driving, but that is the eventual goal.

The 85 kWh version will be available for delivery in December, while the 60D and P85D models will begin delivery in February. The 60D and 85D will carry a $4,000 price premium over their read-wheel drive variants, while the top P85D adds $14,600 to the P85's already high $93,400 base price. Autopilot is rolled into the technology package, which is a $4,250 option. A stripped 60D with no options beyond the base configuration will cost $75,070, while a fully kitted out P85D with every option except for winter tires will cost $137,720 (both prices are without incentives and before taxes).

Musk didn’t have anything substantive to say about Tesla’s upcoming crossover SUV, the Model X, or the $35,000 Model 3 due out in 2017. Rumors have been swirling that the Model X will have a substantially altered appearance from the prototype and demonstration versions of the vehicle that have been revealed so far, but this evening’s event was focused solely on "the D."