The 2018 Mercedes-AMG GLA 45 compact SUV is a bona fide AMG product just like the rest of Mercedes-Benz's high-performance, range-topping AMG lineup: It has a hand-built, 375-horsepower powerhouse engine under the hood and a totally unique driving experience compared with the regular  Mercedes-Benz GLA-Class. The AMG GLA 45 starts life as a little SUV — truly little; the GLA 250 is small for its class — and dumps the ride height thanks to a lowered suspension, then adds 167 horsepower and gets a 167-mph top speed.

New for 2018

There are few changes to the GLA 45 for 2018 besides a slight styling update up front. The tweaked nose has new, vertically slotted grille intakes and a silver front splitter insert. Mercedes-Benz says the slotted grill intakes are functional and help provide airflow to the radiators. Out back, a new diffuser insert adds a racier look, while Mercedes says the roof-mounted lip spoiler is functional.

That all sounded nice — until I gazed upon my Kryptonite Green Metallic test car with an optional high-mounted black rear spoiler and 20-inch AMG multispoke wheels. Around the office, we called it the "snot rocket." At an as-tested price of $71,000, the ostentatious paint and tacked-on spoiler were too much for me. Maybe they would be just the right amount of "Fast and Furious" for you.

Acceleration

Few cars have as big a range of acceleration and throttle responsiveness as the Mercedes-AMG GLA 45 does thanks to its various driving modes. Somewhere between the least-aggressive Comfort mode and the appropriately named — and optional — Race mode, Mercedes seemingly uncorks the engine's additional 167 hp. In Comfort mode, the engine is tame, the turbocharger responds slowly and there's not much oomph under the accelerator pedal. Plus, the transmission shifts lazily. The experience is exceptionally unexceptional.

You better have a clear section of road ahead when you flick into Race mode, because this little booger flat out rips. The transmission builds engine revs from a stop for quicker launches, and the engine comes alive with crisp accelerator response and pulling power; it feels every bit as strong as its 375 hp suggests. It's impressive, especially considering how easy it is for a small-displacement, high-powered four-cylinder to have finicky power delivery, such as too much mid-range power or nothing until the top of the rev range. The AMG has a bunch of punch all over the power band.

You better have a clear section of road ahead when you flick into Race mode, because this little booger flat-out rips.

Race mode isn't viable every day, as the transmission hangs onto gears excruciatingly long and upshifts reluctantly. That was perfect on the racetrack, but less desirable around town. The next-least-aggressive mode, Sport +, is more livable, but still decently peppy around town. 

Ride and Handling

Even the presence of Comfort mode doesn't make the GLA 45 a very livable everyday commuter. Our test car was optioned with the AMG Dynamic Plus suspension, a package for dedicated trackgoers that also includes a limited-slip front differential and Race mode. The optional suspension certainly livens up the GLA 45's handling performance, but it sacrifices ride quality. I did not enjoy driving the GLA45 around Chicago, but wow did it come alive on Joliet's Autobahn Country Club's north circuit, with flat handling and tenacious grip from the all-wheel-drive system that made the track experience a breeze. The GLA45 feels safely planted even near its traction limits — and those limits are pretty high. 

Everyday Livability (or Lack Thereof) 

The GLA 45 isn't a great SUV. It's a fantastic sports car, or perhaps a hot hatchback like a Ford Focus RS or Honda Civic Type R (though smaller). But the backseat is laughably small compared with an Audi A3 sedan or the supersized (relatively speaking) BMW X1 SUV, and that's a fundamental issue with the Mercedes-Benz GLA-Class in any configuration. However, it's less of an issue if you consider the GLA45 a sports car. Sports cars, of course, aren't often purely practical purchases.

Not practical at all are the optional, bulky AMG Performance Seats that jut into the GLA 45's backseat space, but they're grippy and keep a firm hold on front occupants — almost too firm. As a skinny guy, I felt the side bolsters were excessive even with their adjustability fully relaxed.  

For the Money

The AMG GLA 45 is a better impractical sports car than the GLA 250 is a practical small SUV. Despite a small backseat and cargo area, this chassis has more room than coupes like the BMW M2 or Audi TTS, which are around the same price. The GLA 45 we drove was loaded with optional equipment that gave it a $71,000 price tag, but you can get all the important performance stuff in the mid-$50,000 range; it starts at $51,595 with destination.

Audi's RS3 sedan is a more direct competitor, but is available only as a sedan in the U.S. The M2 and TTS are thoroughbreds in this price range, but if you need two more doors and cargo versatility, the AMG GLA 45 nicely fills that void.