Traditionally, buyers select all of the features they want for their vehicle at the time of purchase, and then live with these until buying a new vehicle.

In the future, adding factory features to a car after purchase will become commonplace. In fact, some automakers are already offering such functionality.

Porsche was among the first with its 2021 Taycan, and now fellow Volkswagen Group brand Audi is testing the waters in its home market of Germany, as well as Norway. The first features fall under the categories of lighting, driver assistance and infotainment, and are available for the E-Tron and E-Tron Sportback electric SUVs, as well as the A4, A5, A6, A7, Q5, Q7 and Q8 lines.

For example, in the E-Tron SUVs, an owner is able to upgrade the LED headlights to matrix LED headlights with automatic high beams. Matrix LED headlights enable a vehicle's high beams to be left permanently switched on, as the individual LEDs that make up the headlights can be controlled so as to not blind other road users.

Other features that can be added on-demand include MMI Navigation Plus and the Audi Smartphone Interface. Owners also have the option to extend subscription-based features like those in the Audi Connect suite.

Adding (or extending) the features and paying for them is handled via an app or the myAudi website. After the booking process has been completed, a signed data package is sent to the vehicle via an over-the-air update. The feature is then available the next time the vehicle is started.

What's perhaps most impressive is that there's a one-month trial period option, so you can test out a feature for a month and then choose whether you want to keep it or not. In addition, the installed features remain with the car after it's sold.

Expect the trend to increase as more digital products are developed for cars.