Nothing about the new 2019 Mercedes-AMG GT 4-door Coupe's behavior on a race track really surprises me. The fact that the most potent 63 S model effortlessly eclipses 150 miles per hour down the Circuit of the Americas' back straight and expertly romps around its 20 corners are all things I expect from a car developed by the folks at AMG.

Following the SLS and GT two-seaters, the GT 4-Door is the third purebred performer to come out of Affalterbach, but in a more practical package with seating for four and enough trunk space to swallow groceries, luggage and other necessities. Said another way, AMG has built one serious competitor for Porsche's lauded Panamera.

Track moves

Like other 63 S-badged cars, the AMG GT uses a 4.0-liter twin-turbo V8 firing out 630 horsepower and 664 pound-feet of torque, working its way to the ground via a nine-speed automatic transmission and 4Matic Plus all-wheel drive. Mercedes says the four-door will scoot to 60 mph in 3.1 seconds and hit a top speed of 195 mph, which, considering how rapidly this thing exits corners and builds momentum down straights, I totally believe.

With the car in Sport Plus mode, Power is ready and ample everywhere in the rev range, and the transmission rips off smooth, perfectly timed shifts in its fully automatic setting. For drivers who prefer to be more involved, response to manual shifts using the steering wheel-mounted paddles is instant and satisfying.

The GT 63 S has a number of track-friendly tricks up its sleeve including adaptive dampers with air springs, rear-wheel steering, a rear-axle limited-slip differential and the aforementioned variable all-wheel-drive system. Sport Plus programming yields confident and drama-free cornering with some slight push at turn-in before latching on and tracking through a turn, the meaty 275/35ZR21 front and 375/30ZR21 Michelin Pilot Sport 4S tires providing tremendous grip. There's strong braking muscle from the optional carbon-ceramic discs, too. Everything about my first track run in the GT 63 S inspires tons of confidence and gives a solid first impression of the AMG's incredible prowess.

On my second track stint, Mother Nature decides to dump water from the sky, and track officials mandate that stability handcuffs be fully active before exiting the pits. Instead of 150 mph on the back straight, I only see about 105, with the lead car's rear lights completely vanishing in giant rooster-tails of water. Through turns it's a constant battle to keep the GT 63 S on the pavement, with the rear tires always wanting to step out, but I'm still enjoying decidedly brisk laps considering the very wet conditions. The GT has solid wet-weather track capabilities, though not getting a few more laps on a dry track is seriously disappointing.

Road worthy

Flip the GT 63 S into Comfort mode and it performs like a proper grand tourer. Throttle response isn't as immediate, the suspension softens, the steering lightens -- it all just simmers down. There's a brief lull at throttle tip-in before the V8 madly shoves off. And once up to speed, a cylinder deactivation system surreptitiously works behind the scenes switching between four- and eight-pot operation, depending on load demands to improve efficiency. Official EPA fuel economy estimates aren't available just yet, but chances are if you're really concerned about that, you aren't going for the GT 63 S, or even the 577-horsepower GT 63.

Instead, Mercedes will offer an AMG GT 53 powered by a 3.0-liter turbocharged I6 engine making 429 horses and 384 pound-feet, combined with an EQ Boost mild-hybrid system that provides an additional 21 horsepower and 184 pound-feet for off-the-line acceleration. This is the same engine that's found in the new AMG CLS53 and E53 models, and it's no weakling, resulting in a 4.4-second 0-to-60mph time, while offering ridiculously smooth and linear power delivery. The drivetrain is a sweetheart and all that you need to make the AMG GT 4-door an entertaining daily driver.

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On public roads, both the GT 63 S with its air springs and the 53 with its coil springs and adaptive dampers provide a comfortable ride quality. The 63 S is obviously the sharper tool for backroad blasting, but the 53 still offers nicely weighted, responsive steering. The wide Michelin tires don't fill the cabin with too much unwanted noise, either.

A plush and feature-packed interior

Speaking of the cabin, it's beautifully finished with soft leathers, Alcantara and gloss black trim, and offers spacious accommodations for both front and rear passengers. Even with the fastback roofline, there's enough headroom for adults to comfortably sit in back, and US-market cars get two bucket seats in the rear as opposed to a three-across bench. A high-zoot Executive Rear Seat Package will be optional, which adds a fixed center console with an integrated touchscreen that allows passengers to control interior settings and infotainment functions. The console also has temperature-controlled cup holders, not to mention a couple of USBs and a wireless charge pad to juice up smart devices.

On the technology front, the dash sports dual 12.3-inch screens with reconfigurable layouts and the latest COMAND infotainment -- no, the GT 63 doesn't get Mercedes' new MBUX tech quite yet. Still, COMAND works well, controlling a 14-speaker Burmester audio system, navigation, Bluetooth and Apple CarPlay, but sadly not Android Auto. Audiophiles will have the ability to upgrade to a 25-speaker Burmester system, too. A new center console houses color display buttons with physical switches to adjust volume, drive modes, stability control and exhaust settings. To limit hands-off-the wheel time, the flat-bottom steering wheel uses the responsive and intuitive touchpad system from the E- and S-Class models to control the digital displays.

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For safety, automatic emergency braking will come standard on all GTs. Features like adaptive cruise control, blind-spot monitoring, lane-keeping assist, head-up display and a 360-degree camera are available as options.

Options upon options

As if all the drive modes, gauge themes and seat layouts weren't enough options to digest -- and, frankly, they feel a bit like overkill -- the GT 4-Door will also boast a number of exterior styling packages allowing owners to personalize the already gorgeous wrapper. The most functional one is an aerodynamics package that tacks on a larger front splitter, rear diffuser and fixed rear wing that provides an additional 66 pounds of downforce at 186 mph, compared to the car's electronically adjustable spoiler.

For a sportier look, a carbon-fiber pack sees aero elements and various trim pieces constructed from the woven lightweight material, while folks looking for a more sinister appearance can spring for a Night Package to have them finished in gloss black. To stand out still more, a Chrome Package adds a bright and shiny finish to the front splitter, elements in the front fascia and side sills. It's not gaudy, but not my favorite.

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Coming soon

While the 2019 Mercedes-AMG GT 4-door Coupe will land in European showrooms over the course of the next month, the US will have to wait until next year. Plans call for the V8s to go on sale here during the first quarter of 2019, and the GT 53 will arrive midyear. Pricing isn't available yet, but I'm expecting six figures -- the $104,000 Porsche Panamera 4S matches up nicely to the GT 53 on paper, for example. If the AMG begins below that, it'll be a heck of a bargain.

Either way, you've got some time to mull your dream GT 4-door over before it gets here. From mild to wild, AMG will have a car for you, and after sampling both the base and range-topping models, I can confidently say that you won't be disappointed with any version of this swoopy stunner.  

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