Brabus are at it again, this time turning their attention to the Mercedes-AMG GT 63 S 4Matic+ to create the Brabus Rocket 900 “One of Ten.” As the name suggests, it is a limited-edition model, with just 10 planned for production, with the grey one pictured here said to be priced around 435,800 euros (RM2.14 million).

Meanwhile, the “900” refers to the Rocket’s power output, which is 900 PS (888 hp or 662 kW). That’s quite a jump, considering a normal 63 S 4Matic+ serves up just 639 PS (630 hp or 470 kW). So, what did Brabus do to achieve this?

Well, the company says “there is nothing to replace displacement other than more displacement.” As such, the 4.0 litre twin-turbo V8 gets a special precision-balanced billet crankshaft with a stroke increased to 100 mm, along with billet piston rods, larger forged pistons boring out each of the eight cylinders to 84 mm.

With these changes, the displacement climbs to 4,407 cc from 3,982 cc, with the company optimistically rounding things up to 4.5 litres. The forced-induction system also gets Brabus’ own high-performance turbochargers with a larger compressor unit and a special core assembly with reinforced axial bearing, allowing the maximum boost pressure to be set at 1.4 bar.

That’s not all, as a carbon-fibre ram-air intake system, new high-pressure pumps, a stainless-steel exhaust system (with silent “coming home” and “wake the neighbours loud” modes) and a remapped engine control unit become part of the revamped powertrain. Aside from the increased horsepower count, peak torque shoots up to 1,250 Nm, which is 350 Nm more than stock.

All that grunt is sent to all four wheels via a 4Matic+ all-wheel drive system and a nine-speed AMG Speedshift MCT 9G automatic transmission. Performance-wise, the zero to 100 km/h time is 2.8 seconds (0.4 seconds quicker than stock), while the sprint to 200 km/h takes just 9.7 seconds. For the full gallop up to 300 km/h, 23.9 seconds are required, but the top speed is capped at 330 km/h (15 km/h more than stock) due to the sheer weight of the thing at 2,120 kg.

Large is also apt to describe the forged aero-style wheels, which measure 21 inches at the front and 22 inches at the rear, both sets curiously fitted with Pirelli P Zero tyres instead of something grippier. There’s also the Brabus Airmatic Sport air suspension system to slash 25 mm off the ride height, with two modes – Comfort and Sport – available.

To make sure the Rocket looks as menacing as on paper, Brabus developed a custom widebody kit made from carbon-fibre that adds new wider fenders with integrated sweeping flares. At the rear, these flares add 78 mm to the width to the GT 4-Door Coupe, while the fender liners are made from Kevlar.

The kit also sees larger air intakes at the front to better feed the engine and ram-air intake system, while ensuring aerodynamic efficiency by way of a splitter on the bumper. As for the rear, it gets a multi-piece carbon-fibre wing and a new diffuser element.

Finishing touches to the exterior include bare carbon-fibre panels on various areas, including the side mirrors, while the first example of the car is finished in a Stealth Grey paintjob, with all previous chrome parts painted to match.

Inside, “Brabus Masterpiece” emblems are found on the seats, along with grey seams and piping to contrast the quilted black leather and Alcantara upholstery. The company also ensured 215 parts inside the cabin, from switches to bezels are coated to match the exterior, while various carbon elements, illuminated stainless-steel scuff plates and a “1 of 10” plaque completes the look.