Both versions of the luxury sedan have been spotted undergoing late-stage testing.

We’ve been following the development of the facelifted, 2018 Mercedes S-Class and AMG S63 over recent months, both having been spotted several times testing on public roads. Now they’ve been seen together, testing in Southern Europe.

The cars carry a mixed bag of existing and prototype components. The S63 (pictured here in black) sports heavily camouflaged bumpers - the front more so than the rear. The disguising wrap on the rear bumper appears to hug the contours quite closely, suggesting it hasn’t changed too much over the current car.

The front bumper, however, is almost completely obscured, apart from a pair of square vents cut out over the bumper’s intakes. Those intakes appear to have been completely redesigned - more flowing, better integrated, and perhaps less aggressive than those on the current S63. Previous prototype bumpers were somewhat cruder.

The regular S-Class (pictured here in silver) gives another glimpse of the 2018 car’s redesigned headlamps. They feature parallel lines of LEDs running around the inside edge of the unit, and do double duty as both daytime running lights and turn signals.

The rear bumper is taped up along the lower edge and above the tail pipes, suggesting some minor detail changes. And, like the S63, the front bumper is more heavily disguised, particularly the lower half. So it’s likely non-AMG S-Class models will also have redesigned intakes.

The interior of the 2018 S-Class, as revealed recently, features a three-spoke steering wheel instead of the current car’s model-specific two-spoke item. It also has the dual-screen instrument and infotainment system pioneered on the latest E-Class - the current S has a pair screens separated by a column of buttons.

Mercedes has not yet announced when the 2018 S-Class will be unveiled, but a debut in the first quarter of next year at either the Detroit or Geneva motor shows seems likely.

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