Because what we have here is the German tuner's take on the S-Class, packing a whole lot more power. Welcome to the B63S.
It's the most powerful performance pack available from a trio of upgrades offered by Brabus, the first two weighing in at 520bhp (a simple ECU remap available for the S500) and 650bhp (available on the S63).
But it's the range-topping B63S - 730 that's drawn our attention, chiefly because it gets gold heat reflection on the inlet pipes – a bit like the McLaren F1's engine bay – two special Brabus turbochargers (replacing Mercedes' own blowers) with larger compressor units for higher boost pressures, and a low-temperature water radiator for the intercooling system.
There's a free-flow exhaust system with 3in-thick downpipes, as well as Brabus engine mapping for the 5.5-litre V8. But the real reason it caught our attention is because this performance upgrade unleashes 730bhp – as much as a Ferrari F12 – and 785lb-ft of torque. That is many, many torques. Top speed is "limited electronically" to 202mph. Limited to 202mph. More than any other stat you've just read on this new Brabus, that last one speaks volumes about its power.
You can option a special sports exhaust, too, with a butterfly valve that changes from a discreet “coming home” mode (well, as discreet as a 730bhp über-saloon can ever get), or the full banana “wake the neighbours and terrify the dog” mode (here shortened to “Sport”).
Elsewhere, you can specify a new aero kit to help minimize negative lift (increase downforce, basically), new monoblock alloy wheels ranging from sizes 19in to 21in, special control modules for the Airmatic or active body control suspension that lower it by 15mm, and of course, many exclusive interior options.
No word on price – not even the standard S63 AMG's ticket has been confirmed yet – but the base S63 is expected to cost upwards of £115k.
A version of this story originally appeared on TopGear.com.