German tuning company Posaidon has managed to take one of Mercedes-AMG’s most impressive models and make it even faster. It’s known as the Posaidon GT 63 RS 830+ and is based around the Mercedes-AMG GT 63 S 4Matic+.

Ordinarily, the 4.0-liter twin-turbocharged V8 engine of the GT 63 S 4Matic+ pumps out 639 hp, making it one of the most powerful and fastest vehicles in its segment. Not satisfied with that figure, the tuner has fitted a pair of new ball-bearing turbochargers while also overhauling the intake system, intercooler system, and cylinder heads.

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In its unrelenting pursuit of power, Posaidon has also optimized and expanded the intake and exhaust ports, added water/methanol injection, and fitted a new exhaust system with unique downpipes and high-flow cats. The ECU has also been tuned and the upgraded sedan now delivers 940 hp and 942 lb-ft (1,278 Nm) of torque. Those are some serious figures and the water/methanol injection system is a unique touch, enhancing boost pressures without subjecting the engine to higher thermal loads and running off a tank beneath the floor of the trunk.

In a straight line, the GT 63 RS 830+ dispatches of the sprint to 62 mph (100 km/h) in a mere 2.8 seconds and needs just 5.9 seconds to accelerate from 62 mph to 124 mph (200 km/h). It will also top out at over 217 mph (350 km/h).

Posaidon will only sell its 830+ package to customers outside of Germany. Those who live in Germany will need to settle with 830 hp and 811 lb-ft (1,100 Nm).