Let the big dog eat. I don’t know where the phrase comes from or why people seem to use it for everything from a toddler getting her way to a rare straight drive on the golf course, but it applies just as well to the Mercedes-AMG GLC43.

The big dog here is AMG, the performance division competing with BMW’s M-Series and Porsche’s GTS lineups that grew 33 percent in 2016, according to Automotive News.

GLC is the first smaller dog in the lineup to get the AMG collar. It comes as an SUV or a coupe. Confused? Shopping for a German car might be more challenging than learning the language. Ja. The coupe is a tall fastback crossover that looks silly.

The tester was the SUV, which is really an AWD crossover, that starts about $13,000 more (about 25 percent) than the base GLC. Before options.

For looks, the AMG diamond-pocked grille appears a little taller, or at least more aggressive, and the side air intakes are a tad wider. There’s more chrome lining to make the menacing face wink at vehicles about to be passed. The tester came with 21-inch five-spoke wheels ($1,000 extra) to buff the profile.

It looks dignified yet approachable in the Mercedes way, stands out more than Audi’s Q5 or BMW’s X3 or X5, and is as well-proportioned as the Porsche Macan, though the latter strikes a more aggressive pose.

The GLC43 is the smaller engine option, a 3-liter biturbo V-6 dwarfed by the GLC63’s 4-liter six. The little dog can eat, too.

Driving the GLC43 in sport mode is like walking a young boxer on a leash. For the most part it’s well behaved, but other times at the slightest provocation of the throttle it yanks and lurches ahead.

Getting used to the snarl in sport mode was fun. The biturbo V-6 has no lag, though the 384 pound-feet of torque comes a bit later at 2,500 rpm than the Macan GTS.

At that point, it’s broken the leash and is churning to 60 mph in an estimated 4.8 seconds. It’s breathtakingly quick for a crossover, and the rear-wheel drive bias of the all-wheel-drive system, which is another difference for the AMG line, means there’s plenty of launch from the haunches. It growls and snorts better than most V-6s we’ve tested.

Laying off the throttle and braking in sport mode takes some getting used to; it was too relaxed when driving slow, and too tight when driving hard.

The handling suits the mood, or mode; in sport and sport plus it firms up nicely to tuck into corners, while in comfort mode at highway speed it’s smooth enough to lull the kids to sleep.

Mercedes’ advantage is often its chill cabins, sharp without being ostentatious, loaded without being too overwhelming, and most of all, comfy. The tablet-like display screen could be better integrated into the dash – Audi still has the edge there – and Mercedes finally killed the number pad and claustrophobic center stack for a simpler, horizontal band of buttons for radio and climate.

The controller, however, is as odd as SUV coupes. It’s humped for your palm to rest on or to use as a touchpad, then there’s a push-dial below it to toggle through the various submenus on the screen. It keeps the design uncluttered, but the palm rester/controller overhanging the dial is funky.

Options abound, as they do in any luxury model, and fortunately Mercedes keeps it relatively straightforward, unlike BMW and Porsche, who seem to option even the fine print on all the packages. Premium package ($5,950) has all the modern driver aids, from lane keeping to pedestrian alert, and is bundled with navigation and updates for up to three years.

That’s better for leasing than owning, but at least automakers like Mercedes-AMG are recognizing the need to treat car technology like technology.

The AMG GLC43 isn’t as blistering as the Porsche Macan GTS, but like the Jaguar F-Pace S does a good job of balancing performance snarl with excellent road manners.

Base price: $54,900. As tested: $68,495 (excluding $925 destination).