Road Test Editor Howard Walker uncorks Mercedes’ new four-wheel-drive 
four-banger super-sport sedan.
Trust me, a cork exiting a New Year’s Eve bottle of bubbly doesn’t have anywhere near the ‘pop’ of a Mercedes CLA45 AMG exploding away from standstill. It’s truly a small package with a huge fizz!

Holy crap, this thing is rapid. As in zero-to-60 mph sprinting in 4.2 seconds, according to Motor Trend’s stopwatch clickers. That’s quick. That’s clown-out-of-a-circus-canon quick! To put that in some kind of perspective, it makes the CLA45 more rapid than a Porsche Cayman S; quicker than a 550-horse supercharged Jaguar XFR-S; faster than Merc’s own 6.3-liter 451-horsepower C63 AMG thunderbolt.

So why is this CLA45 so special? Because beneath the curvy hood resides a teeny-weeny 2.0-liter four-cylinder. Yep, a four-banger. But because it’s been crafted by those performance-meisters at Mercedes-Benz’ AMG division, it’s a four-banger that cranks out a quite insane 355 horsepower. Drum roll please; here is quite simply the highest-output four-cylinder engine to ever propel a production car. It’s also the first Four developed by AMG.

In case you’ve been wasting away in Margaritaville for the past year, the CLA is Mercedes-Benz’ brand new entry model; a Honda Civic-sized four-door with a very Honda-like $30-grand starting price. Of course that’s for the base model with front-wheel drive and a 208-horsepower Turbo-Four. Its mission is to lure younger buyers on to the first rung of the M-B ladder and hopefully keep them in the fold for life. But to add a little sizzle to the CLA’s image, and to avoid it being branded a low-cost bottom-feeder, Mercedes sent it off to AMG. The result: a $48,500 fast and furious, four-wheel-drive thrill-ride.

See it in the metal and it looks like a scaled-down version of Mercedes’ gorgeous CLS four-door coupe. Same swoopy roof line. Same stubby rump. Same pinched snout adorned with drop-dead-gorgeous headlamps. And the AMGification includes a razor-edged carbon-composite front aero splitter, stealth-black 18-inch alloys covering massive red-hued AMG stoppers, and a quartet of exhausts emerging from a huge carbon rear diffuser. As for those rear LED lights, they’re nothing less than pure automotive art.

In addition to that potent turbocharged motor, the CLA45 features a newly developed seven-speed dual-clutch 4MATIC automatic that delivers those 355 horses to all four wheels. While the drive system normally acts like a front-drive setup, pour on the power or start carving curves and all 258 pound-feet of torque can be split 50/50 between the front and rear axles.

So how does it drive? One word: Bonkers. Hard on the throttle and play tunes with the paddle shifters and the CLA45 is all head-snapping thrust accompanied by the snarliest of exhaust notes this side of chainsaw on nitro. Mid-range thrust, for passing or freeway merging, is fearsome and more like a V8 in the way it pins you back into the seat.

But it’s not all wonderment. In less pedal-to-the-metal driving, the car feels sluggish off the line before the Turbo spools up. The dual-clutch auto can also feel clunky and crude under light throttle changes. And the AMG-tuned suspension delivers a ride that will chatter your teeth!

For me, however, the biggest question mark hanging over the CLA45 is its sticker. Start checking a few of the options boxes and you can easily end up with a $60k price tag – our test car topped out at $63,415. For the same money you could come close to buying a full-on 6.3 V8-engined Merc C63 AMG. Or a 556-horsepower Cadillac CTS-V.

Maybe selling boatloads of CLA45s isn’t a priority for Mercedes. Just having it in the showroom alongside the cheap-and-cheerful CLA250 is more likely to be the real reason for its existence.

For more information about the latest luxury-performance vehicles from Mercedes-Benz, please visit http://www.mbusa.com/mercedes/index