There’s an even more manic version of the Mercedes-AMG GLA coming: The Mercedes-AMG GLA 45, with 382 hp and 354 lb-ft of torque, will join the GLA 35 in U.S. Mercedes dealerships before the end of the year. Pricing has year to be announced, but don’t expect much change from $55,000.

And what does paying something like $8,000 more than you would for the GLA 35 buy you?

It buys you the world’s most powerful 2.0-liter production engine, for a start. Codenamed M139, and each hand-built by an AMG technician in Affalterbach, it makes its 382 hp at 6,500 rpm, with the 354 lb-ft of torque available from 4,750 to 5,000 rpm, enough to clip 0.7 second from the GLA 35’s 5.0-second zero-to-60 acceleration time.

Although identical in terms of bore and stroke to the turbocharged four that powers the GLA 35 and the regular GLA models, the M139 is a significantly different engine.

Compared with the GLA 35 and other GLA models, the M139 has been turned 180 degrees in the engine compartment so the intake is at the front of the car and the turbocharger and exhaust are near the firewall. AMG says this configuration allows the most aerodynamically advantageous front-end design and more direct air and gas flows on both the intake and exhaust side. Other changes include a turbocharger that not only features a twin-scroll impellor to help with low-end torque and roller bearings to improve response but also has a turbine housing with two parallel flow passages. Divided ducts in the exhaust manifold feed the exhaust flow to the turbine separately to prevent individual cylinders from influencing each other negatively during load cycles, and to improve the gas cycle. The result, according to AMG, is higher torque at lower engine speeds and extremely good responsiveness.

Detail engineering changes include a high-pressure, two-stage fuel-injection system and a cooling system that enables the cylinder head and crankcase to be cooled to different temperature levels—the cooler cylinder head allowing maximum output through aggressive ignition timing, the warmer crankcase helping reduce friction in the bores and crankshaft bearing.

The M139 drives through AMG’s Speedshift eight-speed dual-clutch transmission and the top-end AMG Performance 4Matic+ all-wheel-drive system, which features a rear differential with two electronically controlled multidisc clutches that, depending on the drive mode selected, allow the drive torque to be separately distributed to either rear wheel. Six drive modes are available: Slippery, Comfort, Sport, Sport+, Individual, and Race (which comes with the optional AMG Dynamic Plus package), each changing the characteristics of the powertrain, suspension, and exhaust. In Race mode drivers can also set the stability and traction control systems to Master mode, which sharpens the steering and allows power oversteer.

The standard brake setup is the same as in the GLA 35—13.8-inch rotors and four-piston calipers up front and 13.0-inch rotors and single-piston calipers at the rear. Order the AMG Dynamic Plus package, however, and the front brakes get swapped for 14.2-inch rotors and six-piston fixed calipers. And the brake calipers are painted red rather than silver.

In terms of exterior styling, the GLA 45 has the same toothy grimace as the GLA 35 up front but gets a detached rally-style wing over the rear window and four 3.2-inch exhaust outlets on either side of a more aggressively styled rear “diffuser.” As with the original GLA 45, it has little aero flics on the front corners, but they’re less aggressively rendered.

We liked the previous-generation GLA 45, describing it as a riot on wheels that begged to be driven to wring the engine for all its worth: “Fun! Fun! Fun!” senior features editor Jonny Lieberman raved after sampling it. “This is the Subaru STI wagon replacement we’ve all been waiting for!” But our experience with the GLA 35 has us wondering whether we’ll be as enamored of this second-generation GLA 45. It’s not just that we’re worried the new 45 will have the same poor ride and numb chassis; we suspect that, as with the 2021 GLA 35, the 3.6-inch increase in overall height over the previous model will make the redesigned GLA 45 feel like just another tall, lumbering, overpowered SUV rather than a road-legal rally racer you can hurl down a gravel road with an ear-to-ear grin.

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