Mercedes-AMG CLE 646 Spezialanfertigung Is Even More Ridiculous Than An American Will Sound Pronouncing Its Name
The automotive world has long recognized the engineering prowess of Affalterbach, the historic home of Mercedes-AMG. Over the past several decades, the division has transitioned from an independent tuner of Mercedes-Benz road and racing vehicles to a core, high-performance sub-brand within the Mercedes-Benz Group. While the "Black Series" nomenclature has historically signified the pinnacle of track-focused production models, Mercedes-AMG has unveiled a new, ultra-exclusive chapter in its history: the Mythos Series. The latest entry, the CLE 646 Spezialanfertigung, represents an uncompromising engineering exercise that pushes the boundaries of the modular CLE platform.
The moniker "Spezialanfertigung"—German for "custom-made"—is a direct reference to the bespoke nature of the project. Limited to a global production run of only 30 units, the vehicle has already reached a sold-out status among the brand’s most discerning collectors. This vehicle serves as the second installment in the Mythos Series, following the windshieldless, SL-based PureSpeed. While the broader market anticipates the arrival of the mass-production V8-powered CLE 63, the Spezialanfertigung provides a glimpse into the extremes of what is possible when engineering teams are given a mandate for maximum dynamic performance.
Engineering the Powertrain: The Return of the V8
At the heart of the Spezialanfertigung lies the M177 Evo twin-turbocharged 4.0-liter V8 engine, a powerplant that reaffirms AMG’s commitment to high-displacement performance in an era of rapid electrification. Unlike previous iterations, this unit features a flat-plane crankshaft, a design choice intended to optimize engine response and high-RPM performance. The engine produces a substantial 637 horsepower (646 PS) and 627 pound-feet of torque.
The engineering team has implemented a sophisticated 48-volt mild-hybrid system to augment this output. An integrated starter/generator provides an additional 23 horsepower and 151 pound-feet of torque, aiding in power delivery and efficiency. The torque curve is remarkably broad, with peak figures available consistently between 2,500 and 4,500 rpm. To ensure reliability during sustained track operations, the cooling architecture consists of three distinct circuits: a primary high-temperature loop for the engine, and two secondary low-temperature loops dedicated to the charge air, transmission fluid, and 48-volt electrical components.
The integration of a 9-speed automatic transmission signals a shift in the CLE’s mechanical philosophy, as this is the first rear-wheel-drive, V8-powered AMG model since the discontinuation of the previous-generation C63 in 2023. An electronically controlled limited-slip differential manages power distribution to the rear axle, calibrated to assist in high-performance maneuvers, including controlled drifting under track conditions. Performance metrics reflect this focus: the vehicle achieves a 0-to-62 mph sprint in 3.9 seconds, reaches 124 mph in 11.4 seconds, and is capable of a top speed of 193 mph.
Chassis Dynamics and Lightweight Construction
The Spezialanfertigung is built upon the foundational platform of the CLE 53 but represents a total re-engineering of the chassis and body. Despite the installation of a larger V8 engine and the associated cooling hardware, the vehicle weighs in at 4,178 pounds—a reduction of approximately 375 pounds compared to the CLE 53. This mass optimization was achieved through extensive use of carbon fiber for the bodywork, the installation of a lighter 12-volt starter battery, and the utilization of polycarbonate windows.
Structural rigidity has been significantly enhanced through an integrated roll bar and specialized chassis reinforcements. The suspension, developed in partnership with KW Automotive, utilizes four-way adjustable coilover dampers. These allow for independent configuration of low-speed and high-speed rebound and compression, enabling drivers to tune the vehicle for specific circuit requirements. The track width has been increased by 2.4 inches compared to the base model, and the ride height has been lowered by 0.9 inches in the front and 0.6 inches in the rear.
The connection to the pavement is managed by Michelin Pilot Sport Cup 2R tires, measuring 305/30ZR20 at the front and 335/30ZR20 at the rear. These tires represent a further evolution of the rubber compound utilized on the Mercedes-AMG One hypercar, ensuring maximum mechanical grip. The braking system has also been overhauled, featuring 16.5-inch ceramic discs at the front clamped by six-piston calipers, and 14.2-inch discs at the rear with single-piston floating calipers, all utilizing long-fiber technology for improved thermal dissipation.
Aerodynamic Refinements and Exterior Design
The exterior of the Spezialanfertigung is defined by its widebody silhouette and aggressive aerodynamic profile. The Panamericana grille is the widest implemented by AMG to date, flanked by carbon-fiber intakes and canards designed to channel air efficiently. A notable design feature is the "eyeliner" vents located at the outer corners of the headlights, which direct airflow through the wheel arches and out through louvered vents above the front wheels.
Aerodynamic functionality is adjustable via a manual interface. By adjusting three specific fasteners, the front diffuser can be toggled between "Street" and "Race" configurations. In the race setting, the diffuser functions as an inverted wing, generating a Venturi effect beneath the vehicle. When combined with the rear wing, the aerodynamic package can generate over 550 pounds of total downforce. The underbody has been almost entirely enclosed to reduce drag and improve airflow velocity, further optimizing the vehicle’s high-speed stability.
Interior Minimalism and Functional Focus
Inside the cabin, the Spezialanfertigung deviates significantly from the luxury-oriented interior of the standard CLE. The rear seating has been removed entirely, and the primary front seats have been replaced with lightweight carbon-fiber bucket seats, compatible with optional six-point harnesses. The interior trim features exposed carbon fiber on the door panels, and sound-deadening materials have been reduced to minimize weight.
To maintain a focus on driver engagement, the infotainment system and various electronic assistance features have been scaled back. The steering wheel has been simplified, removing several buttons found on production models, while the driver retains control over nine stages of traction control. This granular adjustability allows for a tailored driving experience that can be adapted to the driver’s skill level and the specific conditions of the track.
Contextualizing the Mythos Series
The development of the Spezialanfertigung began as an internal project by a small engineering team at AMG. Rather than being a collection of disparate performance upgrades, the vehicle was envisioned as a holistic performance system. This approach reflects a broader trend among high-end manufacturers, where engineers are granted more autonomy to develop "skunkworks" projects that test the limits of current manufacturing capabilities.
The implications for the broader Mercedes-AMG lineup are significant. While the Spezialanfertigung is a highly exclusive, limited-production model, the technological lessons learned during its development—ranging from cooling architecture to chassis reinforcement—often trickle down into the "mass-market" performance models. The upcoming V8-powered CLE 63 is expected to benefit from the validation and engineering data gathered during the creation of this project.
Furthermore, the vehicle serves as a bridge to future high-performance offerings. As Mercedes-AMG continues to refine its strategy, the Mythos Series acts as a brand-building exercise that reinforces the division’s commitment to internal combustion and track-day capability. With the automotive industry facing a transition toward electrification, the Spezialanfertigung stands as a definitive statement on the potential of modern mechanical engineering, serving as a precursor to even more radical developments, such as the rumored upcoming AMG GT Black Series. For the 30 owners of the Spezialanfertigung, the vehicle represents not just a collector’s item, but a manifestation of the pure, unfiltered performance philosophy that has defined AMG for over 50 years.
