As I stepped around the corner of the customer lounge at the pristine modernist HWA/Team AMG headquarters in Affalterbach, Germany, there they were on a wall-sized photo collage of AMG history, the founders, Hans Werner Aufrecht and Erhard Melcher. That one photo captures what defines the AMG brand and product.

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It's the early '70s, and these two hard-core Euro hot-rodders are watching over their Frankenstein creation, about to score a stunning upset victory at the 24 Hours of Spa. It's a big, unlikely Mercedes sedan with an enormous, rumbling V-8 and giant flares. So creative, so unique, and more than a little crazy.

Their eyes glint with the passion for performance and motorsports that I share with so many of you, dear readers. So much is written in their faces: determination, enjoyment, intelligence, and mischief.

Nearly a half century later, that passion is very much alive in AMG's latest GT creation.

Mercedes-AMG automobiles are represented by their hearts—the engines. Always modified and muscled-up Mercedes-Benz powerplants, with an aggressive growl from the racy exhaust tips and an instantly accessible flow of torque over a wide range of revs. One man (or woman, I learned) is responsible for one engine, all the way down the assembly line.

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See all 109 photos

Mounted low and well behind the front axle line of the AMG GT, this V-8 is one of my most favorites for its delicious thrust and the basso profundo that accompanies it. The importance of an engine's sonic glory cannot be overestimated in the sporting automobile, and AMG has understood and capitalized on this aspect since the very beginning.

The thundering beast before me today at Circuit Paul Ricard—site of the French Grand Prix again next year—is the AMG GT4. It's designed for the international FIA GT4 class, more street-oriented and less pricey than the GT3 versions we've been seeing in IMSA and Pirelli World Challenge. Even at $239,000, it's roughly half the price of the GT3 mode and about $100,000 more than the street versions.

But where does that money go? Is AMG just charging more for less? I mean, in the GT4, don't they simply use the original car with a lot of expensive interior appointments removed?

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Well, safety is a high priority. The GT4 incorporates all those features found on the GT3, including the rooftop port for better stabilized driver extraction and a seat molded right into the chassis, with pedals and steering that move, instead. The latter arrangement is far stronger than using sliders to both mount and adjust position, and the seat is the foundation of the restraint system.

Another value add is the motorsport gearbox with wheel-mounted shift paddles—again similar to the GT3. The main object here is reliability. Between this purpose-built transmission and the near-stock engine, the AMG GT4 can race for many hours before rebuilds. Pay more up front, pay far less long term, and finish your races. This machine is intended for endurance events, the longer the better. As on the road cars, it's a rear-mounted transaxle for improved weight and mass distribution attached to the front-mid V-8 with the OEM carbon torque tube.

The GT4 also uses the same hot-V twin-turbo as the street cars and, in this application, likely will be producing less power than them, as well, depending on the race series' Balance of Performance (BoP) setting. This means the powerplant will be quite understressed and stay competitive by racing engine standards nearly forever. Strangely, many race cars these days are restricted and actually generate less power than those on our public highways. This is an ongoing trend in FIA and sportscar racing, probably good for the sport long term.

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See all 109 photos

AMG has wisely chosen to go with a motorsport engine management, as well, because street systems are a compromise in the racing environment. This also factors into the price and will be another long-term payoff. More and more these days, it is difficult to nearly impossible to take stock electronics from the road to road racing. Computers tuned for the street get confused and go into limp modes, and stability controls keep rearing their overbearing heads.

Like many of the primary components of the AMG GT4, the chassis is also taken from the road car, a sophisticated and lightweight aluminum space frame with strong torsional rigidity, including the control arms and suspension geometry. The shocks are pure racing components by KW, adjustable for compression and rebound, and the track-specific anti-roll bars are adjustable, as well, to tune to driver preference. On a related note, the GT4 also is equipped with traction control, a large yellow knob front and center on the carbon center console. Although it is my advice to turn that off while you tune shock and bar settings, a little TC in competition makes a great power-oversteer safety net, saves tires, and can genuinely save your Nomex-wrapped behind in the rain.

And it was appropriately damp (and chilly) when I first rolled out of pit lane at Ricard, too. I tested that traction control immediately, set by our AMG hosts to a please-don't-crash Level 2, and it clamped down like a toddler's mom near Niagara Falls. Yet combined with the also-tunable racing ABS, the car was an easy drive in the slimy conditions. From the very start, the GT4 felt brawny, sophisticated, and impressive, but it slewed around a lot on the treaded Pirelli rains as the surface began to dry.

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To my great fortune, I was granted an extra shot just before lunch break, on slicks and a dry track. The AMG delivered neck-straining g's in all directions of the horizontal plane. Fingertip shifts were as quick as thoughts and imperceptible to the seamless thundering flow of power. Going down gears was even better, with perfect roaring rev-matches. A good modern shifter such as this saves many engines and crashes by denying requests made too early, thus preventing over-revs and missed gears.

I could read the suspension tuning—a combination of Euro pro driver snappy turn-in and journalist-safe heavy front anti-roll bar. Steering response was instantaneous. Once the chassis took a set, considerable understeer showed up in the middle of the corner. Our GT4 was happiest in the fast sweeper on the back side of Ricard, where the sizable wing and splitter shoved tires to pavement in a balanced and effective way. In Ricard's many slow corners, there was that strong but safe understeer and rewarding, relentless no-lag thrust on the way out. The brake pedal was a good leg-press workout, and the pedal could go numb (perhaps from ABS) but encouraged an aggressive attack on the entry to the corners, cranking up my adrenaline and cranking out smiles.

In true AMG fashion, the car was refined, elegant, and brutal, all at the same time. The package translates readily to the racetrack, and this piece makes an excellent choice for the gentleman or -woman racer, with its safety, quality, and performance. And it has a downright arresting stance on pit lane.

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See all 109 photos

From the south of France, we jetted to Stuttgart, Germany, and the home of AMG, where I encountered that striking photograph of Herren Aufrecht and Melcher. We witnessed the one builder/one engine philosophy at work, and I successfully located the badge of the technician that built the V-8 in the AMG E63 S we tested the week before for MT. Computers track the tool usage, working in concert with the highly trained and respected engine builders. AMG seeks out Germany's best technicians "that want to build engines." Every engine is cold-dyno tested (turned to 3,000 rpm without running), and at random intervals some get selected for actual firing on the hot dyno.

The AMG line is, "We cannot make Mercedes engines better, only change them." To a performance addict like me, more power is for the better, but best to keep the boss happy. The precision and dedication of the process is admirable.

Next, we stalked the race car assembly area, a true race shop, and I left impressed by the degree to which the GT4 is stripped down and prepared from the bottom up for competition. This is quite the complete package.

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After a test drive and tour of the production facilities, what could be next? How about a visit to the next battle test of these new racers, the Euro-based Creventic 24H race at Circuit of the Americas in Austin, Texas?

I found myself embedded with the Winward Racing/HTP Motorsport team of owner Bryce and lead driver Russell Ward. The team will be running the IMSA Continental Tire Sportscar Challenge Series GS class next season with a couple new AMG GT4s and was selected to run a test car, along with the Black Falcon squad, in another. Russell was joined by pro Damien Faulkner, a friend I met while coaching in the IMSA Porsche GT3 Cup series, and Euro-pros Indy Dontje and DTM hotshot Maxie Gotz. And I was really thrilled to run into a favorite race engineer of mine from Alex Job Racing days, Greg Fordahl. It was a strong lineup.

All four drivers gave glowing reports on the raceability of the GT4, and it showed on track as I watched, nomadically working my around the CoTA circuit. Traffic was heavy, with the GT4s flirting with the top 10 of the 50-plus starters, so passing situations were constant. There were even a couple near-stock Honda Civics and a Peugeot RCZ that looked like a knockoff Audi TT.

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The GT4 entries appeared strong in the brake zones and were often passing two wide around the outside, implying the kind of strong aero grip and stability that encourages aggressive moves. The live in-car video feed showed steady hands on the wheel and no evidence of the skittish corrections of a dicey chassis setup.

The Winward/HTP team led the class for most of the first day (as did its AMG GT3 brother, vying with a 911R for the overall)—the only setback being a tendency to toss off its alternator belt, an issue that only showed up this race with the addition of air conditioning. (Yes, modern FIA GT rules require this for driver safety ... it's hot in there.) Still in the hunt for the class lead 11 hours into the event, both GT4s dropped back when misfires appeared and grew serious, eventually diagnosed by Winward/ HTP as a cranky crank sensor. The team pulled the transaxle and got back in the fight, on the pace, right to the end. At Black Falcon they decided to park the GT4 and focus on the GT3 for the overall.

When the checkered flag fell on Russ Ward in the GT4 after 24 grueling, flat-out hours, Winward/HTP had clawed its way back to midpack, and the Black Falcon GT3 came home a strong second overall to the Porsche.

The AMG GT4 proved itself a gorgeous, imposing racetrack presence with speed and durability to match under tough marathon conditions. One of my favorite road cars has translated into a formidable and enduring competitor, and frankly, I expected nothing less from the company built by those two AMG men in the old photograph, with that racer's gleam in their eyes.

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