The regular E 63 estate isn't due to be revealed until the next Geneva motor show in March 2017, following the E 63 saloon, which is due later this year. But this mule suggests Mercedes is already hard at work developing an even more potent version.
However, an insider has said this car is unlikely to be a Black Series model, despite the claims. Our source said AMG's hottest moniker was unlikely to feature next on an estate. Instead, this mule could be something else to sit above the regular AMG models, or even just an E 63 S.
Although the true identity of the wide-arched test car is still unconfirmed, mules for the regular E 63 estate (below) have been caught on camera on multiple occasions, revealing its large brakes and alloy wheels, quad exhausts and an aggressive front end.