The changes are subtle.

Partially camouflaged 2021 Mercedes-AMG E63 test mules aren’t new. We’ve been seeing the semi-hidden performance saloons and estates for months, and the latest spy video shows Mercedes is continuing the development of the refreshed model. The video shows the AMG E63 saloon with the front and rear fascias still covered in camouflage.

As this is a mid-cycle refresh, changes are subtle and often limited to the front and rear fascias – at least on the outside. The saloon in the video above shows a new, camouflaged grille, which we’ve seen before on other test mules. It’s different than the Panamericana grille it should wear, indicating that the new E63 could receive a new or optional grille design. However, it should still offer the Panamericana grille design.

Other changes at the front include new headlight designs, which look similar to the headlight units on other new Mercedes models. The boomerang-shaped LED daytime running lights are comparable to those on the Mercedes CLS and Mercedes CLA. Updates to the rear appear even subtler. The performance Merc will wear a new rear taillight design, too. We can’t see any changes to the bumper designs, though we expect Mercedes to tweak them slightly before the new model arrives. It’d be unusual for Mercedes not to refresh the front and rear bumper designs.

Gallery: Mercedes-AMG E63 saloon, estate facelift spy video

Inside, we expect minimal changes from the current car. Rarely do mid-cycle refreshes include overhauling a model’s interior. Instead, Mercedes will likely replace the outdated COMAND infotainment system with Mercedes’ MBUX interface. The interior could also receive rejiggered trim packaging.

Powering the Mercedes-AMG E63 will be the automaker’s twin-turbocharged 4.0-litre V8. Right now, it develops 603 bhp in the current E63 S, the top-tier performance trim. However, the engine is capable of delivering 630 bhp, which it does in the GT 63 S Four-Door Coupe.

The 2021 Mercedes-AMG E63 will debut sometime next year, after the regular E-Class facelift debuts, before going on sale.