The last time we caught the upcoming Audi RS4, it was April 2016. At that point, we believed that the super wagon would likely receive some form of electric turbocharging, but since the debut of the 2018 RS5 and its 2.9-liter twin-turbocharged V-6 earlier this month at the 2017 Geneva auto show, our guess is that it will likely use the same engine, though the RS4's variant may be slightly detuned.

Based on these spy shots taken near the famous Nurburgring, the RS4 Avant unsurpringly takes styling cues from the B9 A4 and A5. Unlike the standard models and fitting of the RS badge, the RS4 Avant receives a more aggressive front and rear fascia with a more pronounced lip and rear diffuser.

It also gets a set of RS wheels that compliment what appear to be some truly massive carbon-ceramic brakes housed in the wheel wells. Out back, unlike other RS models of old where four was greater than two, the new RS4 Avant receives a pair of enlarged single outlet exhaust pipes.

If the RS4 Avant receives the 2.9-liter twin-turbocharged V-6 from the RS5, that would give the wagon 444 horsepower and 443 lb-ft of torque, about a 125 lb-ft of torque more than the previous generation. In RS5 guise, these performance statistics allow the car to hit 62 mph in just 3.9 seconds and an electronically limited top speed of 155 mph. Given that the RS4 Avant will likely be a bit heavier, thanks in part to the elongated roof, its performance might be a bit reduced compared to that of its sibling.

As with the RS5, Audi will likely give customers the option for adjustable suspension in the form of its Dynamic Ride Control, the aforementioned carbon-ceramic brakes, RS-tuned steering, carbon-fiber interior trim pieces, as well as a trick differential.

Audi hasn't revealed when the RS4 Avant will debut, but September's 2017 Frankfurt Motor Show is a solid bet. However, for us Americans, the RS4 Avant will likely remain unobtainium as we don't expect it to come to the U.S., where Audi's wagon offerings are limited to the high-riding Allroad.

See all 16 photos