Just days after we caught the BMW M5 testing, its hot Mercedes-AMG estate counterpart has been caught on camera, with large brakes and alloy wheels, quad exhausts and an aggressive front-end giving the model away, despite Mercedes' camouflage.
The model was spotted near Mercedes' test centre near the Nürburgring, which reveals the possible nature of the tests being undertaken.
The E 63 will share its engine with the AMG GT. It's a 4.0-litre V8 that is expected to be tuned to 600bhp; a rise of 51bhp over the current E 63, or 23bhp over the E 63 S. That power figure, combined with Mercedes' reported 100kg of weight savings in the new E-Class, signposts a notable improvement over the E 63's 0-62mph time of 4.2sec.
In the Mercedes-AMG range, the E 63 now sits above the newly introduced, Audi S6-rivalling E 43, which produces 395bhp, and is reported to start at more than £50,000 by officials, although an official price is yet to be confirmed. Despite its previous absence from the E-Class line-up, the E 43 isn't expected to affect sales of the E 63, with different groups of customers targeted for each car.
The current Mercedes-AMG E 63 estate starts from £76,515, but the expected rise in pricing of the E 63's hottest rival, the BMW M5, means that this figure could rise for the new Merc. The E 63 estate is expected to reach the UK in the summer of 2017, after its Geneva show premiere.