When you think about the Mercedes-AMG GT 63 4-Door Coupé, the last thing you think is that it needs more power well Renntech do not agree and they have taken their offering even further than the original 783 HP package.

They have called it the RIIIX and it is their most powerful offering ever combined with a menacing cosmetic upgrade.

The tuning upgrades see the twin-turbo 4.0-litre V8 deliver a radical 1,196 hp and a monstrous 1,257 Nm (927 lb-ft) of torque. This is thanks to all-new Stage II high-performance turbochargers, a re-mapped ECU, a carbon air intake system, high-pressure fuel pumps, and other tweaks.

This potent power output is only available when using 100 octane gas so if you cannot source that liquid gold then you will ‘only’ get 965 hp if you end up putting in 93 octane.

Renntech went and added their own Transmission Control Unit and Drive Control Unit which means the 4-door can sprint to 60 mph (96 km/h) in just 2.44 seconds and go on to complete the quarter mile in 9.9 seconds.

No performance upgrade is complete without an improved exhaust system so the tuner developed a stainless steel upgrade that includes downpipes with 200-cell catalytic converters and performance mufflers. The system reduces exhaust back pressure while increasing sound management through the electronically-controlled exhaust valves.

As mentioned the package includes a carbon fibre aerodynamic aspect which includes a front splitter, front canards, two-piece side skirts, a rear diffuser, and an adjustable rear wing. Wrapping up the changes is a set of Renntech RPS 10.2 forged aluminium rims wrapped in Michelin Pilot Sport 4S rubber.

Should you fancy this insane upgrade, you going to have to dig deep as the package costs $94,980 (approx. R1,8m) without the car.