Tesla Motors CEO Elon Musk captivated automotive and technology enthusiasts alike last week in a way that only few can. The billionaire entrepreneur took to Twitter with a promise to “unveil the D and something else” at a media event scheduled for October 9.

Here we sit a week later with the aforementioned media event in the history books as Musk just wrapped things up in California. Here’s what went down.

The “D” that Musk was referring to is an all-wheel drive version of the Model S, the P85D. In a traditional gasoline-powered all-wheel drive vehicle, a single engine is used to power all four wheels through the use of a driveshaft and other hardware but the new Model S features dual electric motors; one per set of wheels.

The “D” stands for dual motor, Musk noted.

As you may know, the Model S is already quick but with four wheels laying power to the ground, it’s blisteringly fast. Tesla claims the new sedan can accelerate from 0 to 60 mph in just 3.2 seconds. Musk said the car will have three different driver settings: normal, sport and insane.

The added motor also makes the Model S more efficient as it’ll pick up about 10 miles in range per charge for a total range of 275 miles.

The “something else” that Musk was referring to turned out to be new driver assist features. Using an array of sensors positioned around the perimeter of the car, it can change lanes automatically once the driver activates the turn signal.

A new photo and radar system can read speed limit signs and stop signs and adjust accordingly. We're told the radar is effective through rain, fog, snow and sand. There's also the standard-issue features like keeping the car in its lane if it begins to wander or slowing the car down if it’s approaching another vehicle too quickly. What's more, the new autopilot system can even park itself once you get out and (when on private property), you can have the car drive to meet you when you're ready to go.

Musk added that all news cars that have rolled off the assembly line over the last two weeks have the autopilot hardware installed.

Tesla expects to start delivering the Model S P85D to customers in December.