The C8-generation Audi A6 Avant has been spotted running road tests a short while ago, and here it appears that the higher-performance S6 Avant is now doing its rounds for road trials as well. In classic S model fashion, the revisions to the sportier version are subtle almost to the point of anonymity.

Key to marking out the S6 from its lesser siblings is its set of quad tailpipes, while up front a different front bumper with deeper air intakes add to the subtle distinguishing points of the higher-performance family wagon. Very little else marks out the upcoming model’s performance potential, save for a larger wheel and tyre combination, likely housing beefier brakes as well.

Powertrain specifications is where the raw numbers will set the S6 above the mainstream range, though details are yet to surface. The current C7 S6 is powered by a 4.0 litre biturbo V8 producing 450 hp, a figure most likely to be bested with the advent of the new model. The same powerplant produces in the region of 600 hp in RS6 Performance and S8 Plus guises.

It remains to be seen whether the upcoming S6 Avant will follow the bent-eight route albeit in lower tune form, or utilise a breathed-on version of the 2.9 litre biturbo V6 currently used in the RS4, RS5 and the Porsche Panamera S and Cayenne S. What’s for certain is the deployment of quattro all-wheel-drive, with this being a performance-oriented Audi.

With the regular A6 model range expected to make its debut later this year, the S6 should follow closely behind, potentially early in 2019.

GALLERY: C8 Audi A6 spyshots