Is This The Mercedes-AMG GT "53"? Prototype Has Odd Straight-Six Soundtrack

Unlike GT prototypes we've spotted in the past, the one we have here doesn't deliver the unmistakable soundtrack of the M178 4.0-liter twin-turbo V8.

So we could be looking at a new entry-level model animated by the German automotive producer's newly revived straight-six.

Perhaps the machine is powered by the M256 3.0-liter twin-turbo inline-six found on models such as the Mercedes-AMG CLS53 and E53 - those machines see the unit joining forces with a 48V mild-hybrid system to deliver 425 hp and 520 Nm of torque.

Then again, this prototype could simply be testing a new quiet mode for the expected Black Series incarnation of the GT. That would mean one hell of an exhaust setup, though.

You see, now that the Mercedes-AMG GT Pro is out, the automaker is expected to release the Black Series, which should be the definitive range-topper.

For one thing, the aero package found on this test car points to such a setup, as it's even more aggressive than the bits and pieces that keep the GT Pro glued to the road at high speeds.

Regardless of what lurks under that camo, we can tell you this much: check out the clip below and you'll see the Mercedes-AMG GT tester having its way with a G80 BMW M3 prototype. This shouldn't come as a surprise though - the Nordschleife might be the world's longest active racetrack, but with so many prototypes now using the circuit to build handling muschle, such encounters are normal.