Posaidon G RS 850: Mercedes-AMG G63 Tuned to 850hp
German tuner Posaidon has pushed the Mercedes-AMG G63 to 850hp and 996lb-ft, delivering supercar acceleration and a host of chassis and interior upgrades.
Posaidon has taken the Mercedes-AMG G63 and turned it into the G RS 850, a 4x4 with 850hp and 996lb-ft of torque. The German tuning firm’s conversion lifts the luxury off-roader’s performance to supercar levels, with a claimed 0-62mph time of just 3.6 seconds and an electronically limited top speed of 285km/h (177mph).
The G63’s standard 5.5-litre twin-turbo V8 produces 571hp, but Posaidon’s package includes new in-house turbochargers, a high-flow intake and cooling system, and a stainless steel exhaust with sport catalytic converters. The ECU is re-mapped to make full use of the hardware, and the AMG Speedshift Plus 7G-Tronic gearbox receives upgraded internals and software to cope with the increased output.
Chassis and braking upgrades
To keep the G RS 850’s mass in check, Posaidon fits an adaptive damping chassis with three selectable settings. The SUV rides on 22x10.5-inch Y-spoke alloy wheels finished in black, shod with 285/40 R22 high-performance tyres. Braking is handled by carbon ceramic calipers and discs from the Mercedes-AMG S63: six-piston, 420mm at the front and four-piston, 360mm at the rear.
Visually, the Posaidon G RS 850 remains close to the standard G63, but the new wheels and carbon ceramic brakes set it apart. The chassis upgrades aim to improve both ride and handling, making the most of the extra power without sacrificing the G-Class’s off-road ability.
Interior and options
Inside, the G RS 850 features carbon fibre trim and yellow contrast stitching on the seats, dashboard and armrests. The upholstery is finished in quilted leather, and Posaidon offers further interior customisation on request. An optional speed camera warning system can be integrated with the factory COMAND online navigation, alerting drivers to camera locations.
Pricing for the full conversion has not been released. The package is available for current-generation Mercedes-AMG G63 models, and Posaidon states that all upgrades are covered by warranty. For those seeking even more exclusivity, the tuner offers bespoke interior and exterior options beyond the standard RS 850 specification.
Technical highlights
| Base vehicle | Mercedes-AMG G63 |
|---|---|
| Engine | 5.5-litre twin-turbo V8 |
| Maximum power | 850hp |
| Maximum torque | 996lb-ft (1,350Nm, limited) |
| 0-62mph (0-100km/h) | 3.6 seconds |
| Top speed | 285km/h (177mph, limited) |
| Gearbox | AMG Speedshift Plus 7G-Tronic, upgraded |
| Front brakes | S63 AMG, 420mm carbon ceramic, 6-piston |
| Rear brakes | S63 AMG, 360mm carbon ceramic, 4-piston |
| Wheels/tyres | 22x10.5-inch alloys, 285/40 R22 |
