The Audi A4 has been with us for quite a while now, which means it's a perfect time for a completely new model. Spy shots of the standard A4 have already surfaced online, which means that the development of Audi's 3 Series rival is currently underway. However, this particular test mule that we're seeing here is probably not your ordinary A4.

An Audi RS4 in Sheeps Clothing?

Our spy photographer who captured these photos said that this particular test mule had a loud exhaust and because it's being tested alongside the RS6 Avant, we have a strong hunch that what we're seeing here is a mule that's testing the next-generation RS4 Avant's powertrain and driveline.

The latest reports surrounding the RS4 Avant's powertrain indicate that Audi's high-performance wagon will be given a V-6 plug-in hybrid system. A total figure of at least 500 horsepower is expected since this will compete with the likes of the BMW M3 Competition Touring and the upcoming Mercedes-AMG C63 Estate--the latter of which is also expected to come with a plug-in hybrid system.

For now, a charge port isn't clearly seen on this particular test mule--which is a prerequisite of plug-in hybrids, however, it looks like it could be hidden at the left rear fender. It must be noted though that a PHEV sticker can be clearly seen on the left side of the rear windshield.

2024 Audi RS4's Interior

Our spy photographer was also able to capture the test mule's interior. What's clearly prominent are its dual screens, one for the infotainment and the other being the fully-digital gauges. The upcoming Audi RS4 Avant will also adopt the toggle-style shifter of recent Audi and other Volkswagen Group vehicles like the new Golf and Q4 e-tron--for better or worse. Other interior details worth mentioning are the new steering wheel design and of course, the new, more modern dash design.

A Big Step Forrward

As of the moment, the Audi RS4 Avant comes with a twin-turbo 2.9-liter V-6 engine that produces 444 horsepower and 443 pound-feet of torque. This is mated to a seven-speed S Tronic dual-clutch automatic that drives all four wheels. Currently, the RS4 Avant is capable of hitting 100 km/h (62 mph) in just 4.1 seconds, while its top speed is electronically limited to 155 mph.

With the magic of electrification, we can expect the Audi RS4 Avant to not just be more powerful, but also much more fuel-efficient, which is in keeping with the times. As mentioned, we are not sure if this is truly the RS4 Avant, but the sound it produces is a strong indicator that this might be Audi's upcoming high-performance wagon.