New Mercedes-AMG CLE 646 Outmuscles the BMW M4 With 637 HP and a 3.9-Second 0-60 Run, but You’ll Never Be Able to Buy One

Mercedes-Benz has officially unveiled the new Mercedes-AMG CLE 646 Spezialanfertigung, a limited-production performance coupe featuring a heavily upgraded twin-turbo V8, extensive use of carbon fiber, and impressive straight-line speed. The catch? It’s already impossible to buy one.

About 14 years ago, Mercedes-Benz introduced the C63 AMG Black Series, a car that quickly became a modern cult classic and helped shape the direction of AMG performance models. Now, the German automaker has created another highly focused sports car with enough performance to take on the BMW M4.

The Mercedes-AMG CLE 646 Spezialanfertigung will be produced in an extremely limited run of just 30 cars. And if you were hoping to get one, you're already too late. Every example was sold before Mercedes-Benz even announced how much the cars would cost.

Power comes from a 4.0-liter twin-turbocharged V8 that has been extensively upgraded for higher performance. Mercedes-AMG rates the engine at 637 horsepower and 627 lb-ft of torque, with peak torque available from 2,500 to 4,500 rpm.

The engine uses a flat-plane crankshaft and is paired with a new exhaust system made primarily from titanium. AMG also fitted the V8 with a high-temperature cooling circuit and two low-temperature circuits designed to keep the charge air and transmission fluid from overheating under heavy use. A 48-volt starter-generator is also part of the powertrain.

Unlike most modern AMG performance models, the CLE 646 sends its power exclusively to the rear wheels. An electronically controlled limited-slip differential helps put that power down and improves the car's behavior during controlled slides. A nine-speed automatic transmission handles the gear changes.

The result is serious acceleration. Mercedes-AMG says the CLE 646 can reach 60 mph in approximately 3.9 seconds and 124 mph in 11.4 seconds.

The engineers also gave the coupe a more aggressive body designed around performance. It features a redesigned front bumper with a carbon-fiber splitter, a revised hood with an additional air intake, and a massive rear wing. The car rides on 20-inch wheels.

Despite the extensive use of carbon fiber, the CLE 646 still weighs about 4,178 pounds.

To sharpen its handling, Mercedes-AMG equipped the coupe with four-way adjustable dampers and carbon-ceramic brakes. Inside, lightweight front bucket seats replace the standard units, while the rear seats have been removed altogether.

The result is an ultra-limited AMG coupe built more like a collector-grade track weapon than a conventional grand tourer. Unfortunately for potential buyers, all 30 examples are already spoken for.