The story goes that when the Mercedes C63’s inline-four future was decided upon, then-AMG boss Tobias Moers walked out of the boardroom. We get why - one of the AMG C’s biggest selling points is its gargling 4.0-litre twin-turbo V8, but we’re still hopeful the four-pot version might work out quite nicely.
This is it, we’re quite sure. Some sort of AMG’d W206 C-Class was spotted earlier in the year, but the brakes on this one look a little beefier, and instead of oval tailpipes, it has - as per the current C63 - trapezoid exits.
Exhaling through those pipes is likely an evolution of the ‘M139’ single-turbo inline-four used by the Mercedes-AMG A45 S. No other Mercedes four-pot gets anywhere close to its output, although with 416bhp, it’s a long way off the 503bhp offered up by the V8 in the current C63 S.
With four fewer cylinders and one less turbo, it will have a weight advantage, but extra power may still be necessary. Aftermarket companies have shown the A45 engine to be capable of a lot more than 416bhp, but it surely can’t be pushed much further while keeping to strict OEM tolerances. With that in mind, AMG may add some form of electrification to plug the deficit.
There are many unknowns about what’s going on under the bonnet, but there are some more clear-cut things we can see from the spy shots. Along with those beefy brakes (steel, but carbon ceramics will no doubt be an option), the prototype has widened wheel arches, a rear diffuser and additional vents at the front.
We’ll be waiting a little while to see the C63 sans camo - the all-new standard C-Class isn’t going to be uncovered until early 2021, meaning the AMG will be kept from us until the tail end of that year at least. Still, that gives plenty of time to nab a brand new V8 version, should the four-pot not sit with you so well.