Though the spec list for a Brabus 900 model is virtually a given these days, the tuner’s insistence that it force a twin-turbo, 4.4-litre, 900hp, torque-limited-to-774lb-ft V8 into places it really shouldn’t go is hard to resist. Utterly crazy, sure, but irresistible. For all those unsatisfied with the 612hp AMG 63 flagship, Brabus is always on hand to add the best part of 300hp. Legends.

Now that list includes Mercedes’ XL SUV, the seven-seat GLS. So every passenger gets almost 130hp each, which is nice. The Brabus 900 Superblack has apparently been designed ‘specifically for those who view luxury not to be a luxury, but a necessity’ but, of course, we’re rather more interested in what’s under that enormous bonnet. As per other 900s, the 4.0-litre AMG is bored out to 4.4 (4,407cc) and equipped with Brabus’ owns pistons, rods, crank, and turbos. Perhaps more staggering than the headline power is the 922lb ft of torque maximum, reined in to a modest 774lb ft to protect the AMG’s vital internals.

Limited to more than twice the torque of an Audi RS3 is madness. As is the performance: 3.6 seconds to 62mph, and it won’t stop hauling until it hits 205mph, or just a solitary mile per hour less than a McLaren 750S. No less incredibly, Brabus claims 23.7mpg and 273g/km, which doesn’t seem bad at all.

Predictably enough, everything else about the Brabus GLS is enormous as well. The 24-inch (!) forged wheels sit on 295-section front tyres and 335-section rears, so massive that even Brabus’ design of brakes looks a bit weeny behind them. A new air suspension model drops the ride height an inch, enhancing the ‘signature Black and Bold looks’ and hopefully keeping the big brute somewhere near tied down.

That’s about it for the mechanical upgrades, with the rest of the Superblack modifications rather given away by the name. If it can’t be carbon for the GLS, it’s black, from rear diffuser to front spoiler and brake caliper to ‘seashell diamond’ seat quilting. The only thing that isn’t black is the Shadow Grey window glazing. But then, as Brabus insists, ‘it’s always better in black’. Ain’t that the truth? Even a year after its 45th anniversary, there are a few ‘77’ logos dotted around to remind Brabus drivers of the year it was formed.

The Superblack 900 is available to order from Brabus now but, also in keeping with 900 tradition, the demo car is also for sale. At, um, €442,121. And 41 cents. Or more than £390,000 – yikes. But then bored out AMG V8s never did come cheap. Even if a standard (and very black already) GLS 63 does cost more than £200k less, that doesn’t have 900hp. And if you can have 900hp, you probably should…