The quantum crushing engineers over at AMG have summited many a nerd apex. They’ve obliterated previously held thresholds time and again since the company’s formation in 1967, and have continued to do so throughout their partial sale to Mercedes-Benz in 1990 and their eventual complete absorption under the Daimler AG umbrella in 2005. And with their newest tender-footed wolf cub yipping from the litter, the CLA45, AMG has once again achieved a milestone.

With a whopping 360 horses bored, direct injected and forced induced from its forged steel and sand-cast aluminum 2.0-liter engine, the CLA45’s diminutive powerplant is the most powerful 4-cylinder ever made in a production car. That alone is an accomplishment, but not one that satisfied AMG. Its twin-scroll turbocharger forces 26.1 psi into the cylinders, creating a power-to-liter ratio so astronomical that it makes CLA45 the world’s second most powerful engine in that metric. Who beats it, you ask? Why just the $1.15 million McLaren P1 hypercar, is all.

Like all AMGs, each one of the CLA45’s brilliant engines are built by hand, one engineer charged to each one that ships out of the factory. There’s even a signature on the engine block, just in case you want to send flowers to Affalterbach. Add to that the CLA’s stellar “four-door-coupe” looks and you should have on your hands an unbeatable machine, a car that demands to be driven, and purchased, by those with discriminating tastes.

But… not exactly. While the engine on paper seems to tick every need, in action on the field it has its limitations. First off the turbocharger takes awhile to spool up, so you don’t start feeling any power until the revs hit about 2,400 rpms. With a small displacement 4-cylinder this means a very tepid, non-AMG-like off-the-line launch. The lag is manageable once the CLA45 gets going; if you stay active on the paddleshifters you can keep the car in the sweet zone, with considerable power accessible in mid bandwidth of its revs. If you engage the launch control program and are quick with the shifts, it’ll hit 62 mph in just 4.6 seconds, and the dual-clutch seven-speed transmission is sharp and crisp, allowing for an engaging driving experience.

But even with active shifting, no matter how much wizardry is going on under the hood there’s no fooling you into believing there’s one of AMG’s signature fire-breathing V8s under the hood. The previous entry-level AMG, the C63, is a goddamn rabid dire wolf, frothing and gnashing at its leash to the point where the car is actually scary. You feel the 451 hps bellowing forth from its 6.2-liter lump right from the giddyup, and corralling them as you attempt to keep its ass in check on twisty roads is a sweaty thrill from ignition to shutdown. The CLA45 for all its engineered virility may have dire wolf DNA, but it’s just a pup nipping at your self-image of a rock star, not challenging it.

Hit the Jump to keep reading our testdrive of the 2014 Mercedes-Benz AMG CLA45…

“It’s an unbeatable machine, a car that demands to be driven by those with discriminating tastes…”

Of course the CLA45 is cheaper than the C63. The base price for the CLA45 is $48,350, and Benz execs promise that most transactions will land around the $55,000 mark (carbon fiber trim, Multimedia package and panoramic roof are some of the expected popular options). Yes the C63 base prices at about the same level, but its average transaction cost is over $70,000. That fifteen grand is a significant chunk of change and should allow a younger, less financially endowed owner to get his eager hands on his first AMG fob. Then once he’s in the AMG den, the crucial idea is to keep him loyal, moving up the performance catalog — which is the whole point of Affalterbach even touching a 4-cylinder car. But does it counterbalance the risk in AMG reaching further downmarket, potentially watering down its well-earned performance pedigree? “We used to use 4-cylinder engines to power our windshield wipers at AMG,” noted executive Mario Spitzer at the launch. While this was said with a chuckle, there’s probably more than one lifelong AMG enthusiast shuddering at the very thought.

That’s not to say the CLA45 is not a true dyed-in-the-wool AMG. When we were finally able to take it off the commuter roads near Hanover, Germany, and get it on the Bilster Berg Racetrack, the CLA45 impressed. In these controlled conditions you could really push the car to levels that weren’t quite testable on pedestrian streets, and in these more extreme conditions is where the AMG influence was felt. While its engine performed better on the racetrack, the AMG Sports Suspension really differentiated the CLA45 from its commonfolk CLA250 brethren. Bilster Berg is the first new track in Germany in over 80 years, and its blessed/cursed with considerable elevation, off-camber corners and blind straightaways after hills that shock the hairs in the back of your neck to attention. Just days after its opening we rode the virginal black asphalt, breaking in corners with tightly wound racing suspensions working in unison with their 4MATIC transmissions. The results were impressive; the car exhibits no roll with just a little slipperiness in the hairiest corners. While the CLA45 is technically AWD and can send power to all four wheels, in cruising mode the car is really driven by only the front wheels. Put the car through its paces, or set it to Sport Plus mode and the AMG’s brains go in full Fred Astaire mode, keeping all four wheels tapping to make sure you stay on the dancefloor.

“We used to use 4-cylinder engines to power our windshield wipers at AMG…”

So if the CLA45 is an able track star then what, if anything, is the problem? Whether its the Fiat Abarth 500, Mercedes-Benz C63 Black edition, Audi RS5 or BMW M6, as a petrolhead you almost always yearn for, and suggest to others, the top performance model. The more torque, the more Gs, the more bragging rights, the better. But the CLA may be the first car I would suggest in its more pedestrian version. What makes the CLA250 so extraordinary is its value, the quality of car you get for the money. When you nearly double that price, you’ve eroded its best selling point. I love the idea of the CLA45, love the effort and love the execution, but I seriously question its market. Is it for rich kids getting their graduation present? The CLA250 is already for them. Super rich kids? Well they would probably bypass the CLA entirely and go for a C63 Coupe or BMW M3. Unless they’re about to start a family and could really use the four doors. Well then you could get a fully loaded Cadillac ATS and still have some healthy coin left over to kickstart your kid’s college fund. So who’s left?

It makes sense for AMG to push for this car from its Mercedes-Benz partners; the CLA45 will open doors to a whole new crop of potential buyers. And it will certainly be a major catalyst in AMG’s “Performance 50” plan, where they hope to boost sales from the current level of roughly 20,000 units per year to more than 30,000 by 2017 (AMG’s 50^th Anniversary). Without the CLA45, they will have no chance to reach those benchmarks. But when you have a car as good as the CLA250, convincing a young buyer to drop 50% more for a high-revving boost in power may be a tough sell.

The gorgeous “4-Door-Coupe” lines of AMG’s latest track killer…