Brabus Rocket 900: 662kW executive jet

If you thought the recent Brabus-tuned 625kW Mercedes-Benz S-Class Coupe, dubbed the world's fastest AWD coupe, was mad, then check out the Brabus Rocket.

It's completely troppo.

German tuning guru Brabus, which usually confines itself to working on Mercedes-Benz (and smart) models, has turned the crazy meter up to maximum, unleashing the Brabus Rocket 900, whose 6.3-litre twin-turbo V12 bangs out the same amount of torque as the highest-performing Bugatti Veyron – 1500 Newton metres!

The Rocket 900 sets a new benchmark "for high performance in the luxury class" insists Brabus, whose force-fed 12-cylinder engine propels the lavish rear-drive sedan to 100km/h in just 3.7 seconds.

It sprints from 0-200km/h in 9.1 seconds and top speed is "in excess" of 350km/h or 217mph. That's fast, probably too fast.

Although it's not as rapid as Brabus's AWD super coupe mentioned above, the new S-Class limousine has more torque to pin you back in your seat when accelerating. Boasting 1500Nm of the stuff from 4200rpm, the Rocket's output rivals that of the 8.0-litre W16 quad turbo Bugatti Veyron, which for a decade has been the quintessential supercar, but is now set to be put out to pasture.

But Brabus is hoping to tempt savvy executives into its ultra-powerful limousine by touting its intense torque generation at a fraction of the price of an 880kW Bugatti. The latter's average price is around $A3.3million but at 'just' 350,000 Euros – roughly $A500,000 – well-heeled customers could buy almost seven of the Benz behemoths for the price of a single Bugatti.

But there is one caveat – Brabus says "In the car this figure is limited electronically to 1200Nm".

Disappointing, yes, but it's most likely imposed to preserve the transmission, a seven-speed auto bolstered by a Brabus high-performance limited-slip differential "with a locking rate of 40 per cent" says the company. And knowing Brabus, there probably is an option to get the extra hot version anyway.

The most significant change to the twin-turbo V12 engine is the addition of a longer stroke crankshaft and large cylinder bores that increase engine capacity from 5.5 to 6.3-litres, or from 336 to 384 cubic inches. Other mods to the engine internals include new pistons and precision-balanced custom billet con rods.

Brabus then ditches the regular turbochargers and replaces them with a larger pair, modifies the exhaust and intake manifolds and adds a stainless steel high-performance exhaust with "actively controlled butterfly valve" for extra bark.

The fuel-injection and ignition mapping is adjusted accordingly and voila, 662kW at 5500rpm and 1500Nm at 4200rpm.

Despite the monstrous thump, Brabus reckons the Rocket 900 is roughly as efficient as an Australian-made six-cylinder large car, with highway consumption rated at 8.6L/100km and the combined highway/city cycle at 11.9L/100km.

But Brabus doesn't just fettle the engine. Oh no.

The chassis gets a rework, with bigger 22-inch wheels shod with 255/30 front and 295/25 rear rubber and a specially calibrated Brabus Airmatic Sport system that lowers ride height by 15mm "without compromising the outstanding ride quality".

As the photos show, the vehicle has a bold 'aerodynamic enhancement' kit that was optimised in the wind-tunnel says Brabus, featuring extensive use of carbon-fibre. The front bumper is new, featuring a lip spoiler and 'goatee' carbon-fibre air intake accentuations, while the exotic-weave material is also in evidence on the mirrors, front guards, rear lip spoiler and diffuser – the latter featuring a custom-made and integrated quad exhaust system.

Mechanically the Brabus Rocket 900 is off the scale, but the German automotive tuning group also spends a lot of time working on the cabin too, with a range of custom leather finishes available. It also offers its "iBusiness" multimedia system that integrates with Apple consumer electronic devices to provide a seamless experience.

This comprises a retractable drawer in the boot that houses a Mac mini that controls all other peripherals – including an iPad mini that docks "perfectly into the rear compartment" via a specially made console between the two individual rear seats.

There's even a 'BRABUS Remote' app allowing owners to control most car functions remotely. Too bad if you prefer Android-compatible products...

But the most important interior feature? Indubitably the 400km/h speedometer.