UMHLANGA, KwaZulu-Natal – It’s not easy being top dog. Just ask the Mercedes-Benz S-Class, a perennial pack leader that has become exceptionally adept at swatting away competition from increasingly capable rivals on its way to victory after victory in the luxury car category of CAR magazine's annual Top 12 awards.

Still, the Baden-Württemberg-based brand is well aware that it’d be downright foolish to rest on its laurels at this point, with progressively polished versions of its traditional limousine rivals (we’re looking at you, Audi A8) now backed up by an assemblage of über-posh, SUV-shaped offerings conceived to tempt the chauffeured from their plush perches in the hind quarters of stretched saloons.

So, since the S-Class has been around in W222 guise since 2013, it’s high time for an update (although, interestingly enough, this time round South Africa will get V222 long-wheelbase derivatives only, with Mercedes-Benz SA saying that its customers prefer the extra 130 mm between the axles). And, while a glance at the accompanying images may suggest that this facelift is little more than a visual nip-and-tuck – a fresh grille here, a splash more chrome trim there and extravagant crystal-look lamps round back – it’s beneath those familiarly taut lines that the most significant changes have taken place. As many as 6 500 changes, according to Mercedes.

Along with the adoption of the latest version of Benz’s dual-display widescreen cockpit, a redesigned multifunction steering wheel (now hosting the touch-sensitive controls we first experienced in the E-Class), further fettled intelligent suspension and yet more advancements in driver assistance technology that move the Sonderklasse one step closer to fully autonomous capability, the refreshed S-Class also gains a few new powerplants.

One such unit is a certain 2,9-litre inline six-cylinder (the brand is steadily moving away from the V6) that renders the S400d L in which it resides the most powerful diesel vehicle in Mercedes-Benz’s storied history. Sure, 250 kW is plenty for a sub-3,0-litre oil-burner, and sees this particular derivative outpunch rivals such as the BMW 730d and upcoming A8 50 TDI, but it’s the towering peak torque figure of 700 N.m that is more pertinent in a stately saloon such as this.

While foregoing the 48 V electric assistance enjoyed by similarly sized petrol engines doing duty in some models overseas, the new turbodiesel still manages to deliver its maximum twist to the rear wheels across a pleasingly broad band (starting as low as 1 200 r/min), lending the two-tonne luxury barge startling in-gear verve – facilitated by two-stage turbocharging and emphasised by an intuitive nine-speed automatic transmission – and damn-near missile-like overtaking abilities.

Compared with the old V6 oil-burner, this new engine is noticeably more hushed, too, with little more than a whisper making it to the ears of the occupants stretched out in the admittedly meticulously insulated (and fastidiously finished) cabin. It’s considerably more frugal, too, sipping at a claimed 5,2 L/100 km in rear-wheel-drive guise, although that’s more the result of Europe’s ever-tightening emissions regulations than a concerted effort to save the typical S-Class owner a few bucks at the pumps.

As one might expect, the S-Class rides with aplomb, positively dissolving even harsh road imperfections, particularly if endowed with the relatively high-profile rubber (interestingly, 245/45 R19 fore and 275/40 R19 aft) worn by our test vehicle. Eminently comfortable and quiet this swoosh sedan most certainly still is.

Ultimately, a multitude of subtle changes, along with more obvious updates, such as the addition of this silky smooth yet deceptively brawny diesel engine, combine to keep the technological tour de force that is the S-Class one step ahead of the competition. Another trophy in the bag? Surely...

Original article from Car