A plug-in hybrid Audi A4 mule, potentially an RS4, has been snapped testing in Europe.

    The wagon (or Avant in Audi speak) wears a subtle PHEV sticker on its rear windscreen, and was testing with an Audi RS6 on public roads.

    Our spy photographers report this mule was singing a much louder tune than a standard A4, suggesting it’s actually being used to test the powertrain for the hot RS4.

    The body of this car isn’t nearly wide or aggressive enough to be a look at how the production RS4 will shape up, however.

    When it launches, likely in 2023, the new RS4 will go head-to-head with the Mercedes-AMG C63 and its new plug-in hybrid setup. It’ll also take on the non-hybrid, turbocharged inline-six BMW M3 Touring.

    Autocar reports the next RS4 may use an evolution of the current twin-turbo 2.9-litre V6, with the plug-in hybrid system boosting outputs beyond the current car’s 331kW and 600Nm.

    The Porsche Panamera 4 E-Hybrid, which rides the MSB platform and not the RS4’s MLB underpinnings, features a plug-in hybrid twin-turbo 2.9-litre V6 producing 340kW.

    Inside, the new A4 will follow the Volkswagen Golf (and its platform mates) in ditching buttons behind the wheel.

    New images of the interior show a widescreen touch display will dominate the dashboard, and will swallow up the physical climate controls that feature on the current model.

    Along with the touchscreen, the driver will be faced with a new digital instrument cluster that pokes up from the dash. It’s not integrated into a binnacle like the unit in current Audi cars, instead following in the footsteps of the Volkswagen ID. range.

    As for the outside? With its slimmer grille and headlights, along with its more prominent lower air intake, the A4 likely to launch in 2023 will be brought into line with new models such as the A3 and Q4 e-tron.

    The rear is heavily camouflaged, but the roof line appears similarly sporty to that of the current model.

    Like the current car, this A4 Avant prototype has a sharp crease above the rear wheel arch that fades out, a design feature which has become a staple on recent Audi vehicles, including the Q4 e-tron electric crossover.

    The next Audi A4 might be the last to feature petrol and diesel engines, with Audi planning to cease the sale of cars with internal combustion engines outside of China by 2033.

    With the Volkswagen Group investing heavily in a number of electric vehicle-specific architectures, we expect the new A4 will use an updated version of the existing MLB Evo platform.

    Although our spy photography agency only photographed the A4 wagon, the next-generation range should include a sedan, as well as a lifted and off-road-flavoured allroad variant.

    MORE: Everything Audi A4

    Scott Collie

    Scott Collie is an automotive journalist based in Melbourne, Australia. Scott studied journalism at RMIT University and, after a lifelong obsession with everything automotive, started covering the car industry shortly afterwards. He has a passion for travel, and is an avid Melbourne Demons supporter.

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