2014 Mercedes-Benz CLA45 AMG - front three-quarter view - white - live on stage at 2013 NY Auto Show

Remember when 100 horsepower per liter of displacement was a huge feat of automotive engineering? That sort of power density was the preserve of high-strung motorsports powerplants and a handful of street engines not long ago. Well, today Mercedes has introduced its 2014 CLA45 AMG, and it cranks out an astounding 355 horsepower and 332 pound-feet of torque from just 2.0 liters. That’s 178 horses per liter on pump gas in the high-performance version of Mercedes’ entry-level model here in the States. Mercedes calls it the most powerful series-production four-cylinder engine in the world, but we just call it awesome.

Of course, with that much turbocharged authority, it’s no surprise that the racy four-door puts its power to the ground through a version of the automaker’s 4MATIC all-wheel drive system. This most-powerful version of the CLA-Class will run to 60 mph in just 4.5 seconds and nuzzle up against 155 mph before an electronic nanny spoils the fun.

To keep things under control, the A45 AMG receives a new four-link rear suspension and firmed-up components all around. There’s even an active exhaust system similar to that of the SLK55 AMG, which Benz tells us sounds particularly excellent when the seven-speed dual-clutch gearbox is executing rev-matched upshifts and downshifts.

The CLA45 AMG is scheduled to hit US dealers in November wearing a starting price tag of $47,450 (plus $925 in destination fees). Our interest is piqued – is yours? If so, check out our high-res galleries and then scroll down to watch a video and see the official press release.

Related Gallery2014 Mercedes-Benz CLA45 AMG: New York 2013

By Chris Paukert