Although on the surface it looks like a Mercedes taxi, the new Brabus Rocket 900 based on Mercedes S65 AMG W222 is currently the maddest four-door luxury saloon in the world. Packing a 900 horsepower V12 engine, the car is as fast as a McLaren P1 with a top speed of 350 km/h, and yet it can carry four adults in utmost comfort and luxury.

The coolest part of the Brabus Rocket 900 is, of course, its engine. It is the Brabus-tuned version of AMG’s 6.0 liter V12 bi-turbo engine which they have equipped with modified turbos and intercoolers, custom exhaust system, and new software, in addition to new pistons and rods and stuff. The unit now has an output of 900 horsepower and over 1,500 Nm of torque which of course had to be limited to around 1,000, otherwise it would shred the gearbox to pieces.

It is a characteristic of a V12 engine to be rather quiet, especially one equipped with two massive turbos. But Brabus realized people who buy a 900-ho super saloon would want the car to sound like it’s got a pair. So they came up with a custom exhaust system for the Brabus Rocket 900 with a valve control system that features a volume button, so you can choose how loud you want it to be. Here’s a demonstration of how it works:

Performance aside, Rocket 900 also comes with a bespoke body kit that is still fairly subtle when compared to the works of tuners like Mansory, but gives the W222 a more purposeful and aggressive look. It also helps with cooling and enhances the car’s aerodynamics.