When it comes to the modern-day straight-six, the M 256 is a force to be reckoned with. That’s the designation for the most powerful straight-six engine in the current Mercedes-Benz lineup, which also happens to be the most powerful straight-six engine on the road today. The once-famous straight six powered virtually all manner of sports cars, sedans, and 4x4s over the years. It has remained a BMW signature, with original copies using natural aspiration and plenty of revs to go down in history as some of the all-time greats.
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