The expert then points to the Roadster’s aerodynamics beyond its distinctive Panamerica grille. The bar stills as Letzel explains how the grille improves the car’s air flow and stability and how a light carbon-fibre thing in the underbody uses the “Venturi effect” to suck the car to the road. The convertible was also built for hills and curves, especially with rear-steering, he says, adding: “With the top down, you can hear the beautiful sound of the AMG engine.”

Letzel also reveals how the GTC Roadster can be cooled by the opening of 14 vertical fins under the grille. An AMG devotee in tortoise-shell frames nods. Such electronics are welcome in Hong Kong’s notorious heat and humidity.

The engineer closes his hour-long presentation to warm applause. Mercedes-AMG is in overdrive in its golden anniversary year and has flattered Hong Kong by reminding its rich that they are still an important, regionally trendsetting market. Mercedes-AMG sent a range of cars, including perhaps its most precious classic, the “Red Giant” of 1971, the AMG 300 SEL 6.8.

Furthermore, Hong Kong was not another stop on a Mercedes-AMG anniversary tour to mainland China, but a mission in its own right as Asia’s most “mature” market for luxury cars. And that was no wonder as many of our city’s rich have been raised in Mercedes-Benzes for generations and a few have quietly raced AMGs on cross-border flits for years.

Letzel soon learns how rich Hongkongers do their luxury marque homework and ask technical questions. A 30-something in chinos and Ralph Lauren pastels discusses big engines; a fogey-framed professional in tasselled loafers speaks fondly of the Mercedes-AMG GT3, which won the first four places for teams at last year’s ADAC Zurich 24-Hour race on the Nurburgring. Meanwhile, a petite fashionista with a keen eye for design debates the curvature of the GTC’s Panamerica grille with her German host, who then points to the metal’s intricacy.

A few supercar fans gather as the South China Morning Post invites Letzel to name his favourite cars. He had previously described how AMG was founded in Burgstall, Swabia, in 1967 by Hans-Werner Aufrecht and Erhard Melcher as an “engineering office, [carrying out] design and testing for the development of racing engines”. The letters AMG stood for Aufrecht, Melcher and Großaspach, which was Aufrecht’s birthplace – and naturally, Letzel named the “Red Giant” his first pick. The second-placed star of the 1971 Spa-Francorchamps 24-hour race put the marque on the race-tuning map and led to the 1976 opening of the marque’s plant in Affalterbach, about 30km northeast of Stuttgart, where the company evolved into a manufacturer of sports saloons and coupés. Letzel then cites the 1987 “Hammer” as the 360hp W124 E-Class coupé that “opened the way for Mercedes-Benz’s transition from motorsport to tuned cars you can drive every day”.

The 1993 C36 AMG was also the marque’s first marketed collaboration with Daimler-Benz, Letzel adds. He then cites the gull-winged Mercedes-Benz SLS AMG, “the first vehicle to be developed entirely by the unit”. Launched at the 2009 Frankfurt car show, the supercar had a 571hp AMG 6.3-litre V8 that was assembled according to the marque’s “one man, one engine” production principle and fitted to a chassis and aluminium bodyshell produced by Magna Steyr in Graz, Austria. The 1,620kg supercar belted 650Nm of torque to achieve 100km/h in 3.8 seconds and top at 317km/h. The SLS became a collectors’ item, Letzel says.

AMG never looked back after that. In 2011, it created the SLS AMG GT3 for the track, the first customer sports car in Mercedes-Benz history. The front mid-engined Mercedes-AMG GT followed three years later. “It went for a new segment and competed with the Porsche 911, Aston Martin Vantage and the Jaguar F-Type,” says Letzel, who drives a Mercedes-Benz GLC 220 diesel. The marque launched it with a light aluminium spaceframe and a new AMG V8 biturbo engine, with 462hp in the GT (now 476hp) and 510hp in the GT S (now 522hp).

AMG also makes the core eight-cylinder models in the 63 series, with the 45-series compact-entry vehicles for younger drivers. However, Letzel’s favourite AMG seems to be the GT R (HK$2.89 million), the new range topper with a 586hp twin-turbo four-litre V8. Built with virtually the best of Daimler, it was also best known for sporting a new metallic “AMG green hell magno” as a tribute to the Nurburgring race track where it was developed. The 1,630kg supercar tonnes in 3.6 seconds and tops at 218km/h via an AMG seven-speed dual-clutch transmission.

Mercedes-AMG’s private sessions seem a branding success. “We had about 300 VIPs [in seven sessions] over the weekend,” a Mercedes-Benz spokesman said on Monday. “It was a great opportunity to promote AMG and its history in its 50th anniversary year; and it gave the VIPs a chance to view the new AMG GT C Roadster closely.”

After Letzel’s select talks, Hong Kong’s other luxury marques now seem rather quiet.