This improved S-Class features more than 6000 fresh components and various new engines. The key news is that the 3.0-litre V6 diesel that's been used in volume versions of the S-class since 2005 has at last been replaced. Instead, customers are being offered a completely new 2.9-litre in-line six cylinder diesel motor developing 286bhp in the base S350d. This powerplant uses variable valve lift control for the first time and is mated to a new, even smoother 9-speed 9G-TRONIC auto gearbox. In the S350d, 62mph from rest takes just 6.0s en route to an artificially-limited maximum of 155mph and on the move, the electronically controlled air-sprung suspension delivers ride quality that rivals can't quite match. Its incorporated MAGIC BODY CONTROL' set-up now incorporates a further curve-tilting function that tilts the body by up to 2.65-degrees through the bends so that passengers will hardly notice it as you go through tighter turns.
Other engines on offer in the line-up are all petrol-powered. They include a 3.0-litre petrol V6 with 457bhp in the S500 variant that'll be a rare sight on our roads. The top Mercedes-AMG S 63 variant gets an AMG-developed 4.0-litre biturbo V8 petrol powerplant with 612bhp to replace the previous 5.5-litre V8. The top S 65 gets a twelve cylinder 6.0-litre 630bhp unit.
We may be talking about a facelift here, but it's the most extensive model rejuvenation of any that Mercedes has undertaken in its entire history. You wouldn't really know that from a glance at the exterior of this car. Its dimensions are unchanged, so it remains 5,125mm long in its standard form, or 5,255mm in length in its long wheelbase guise. Changes are limited to details things: the prominent chromed front grille has been updated, as have the bumpers and the graphics of the LED headlamps and tail lights.
Inside, the cabin materials are of an even higher grade than before, but otherwise, the spacious interior will be familiar to previous buyers of this sixth generation design. That means the front of the cabin continues to be dominated by two 12.3-inch screens and uses touch-sensitive steering wheel controls. New is an 'Energizing Comfort Control' package that links together various comfort systems in the vehicle: you choose a mode ('freshness', 'warmth', 'vitality', 'joy', 'comfort') and the set-up uses a range of various elements - interior climate, music, massaging seat settings, cabin fragrance and so on - to deliver a co-ordinated 10 minute programme aimed at re-vitalising you. On a more practical note, there's a 510-litre boot.
As before, most S-Class models will continue to be sold in the £75,000 to £90,000 bracket, but it's perfectly possible to pay up to and over £200,000, if you choose a well-specified Mercedes-AMG S 65 or Mercedes-Maybach variant. There's a £2,800 premium to go for the standard bodyshape to a long wheelbase version.
A key draw this time round will be the improved 'Intelligent Drive' driving assistance technology on offer which takes another step towards fully autonomous driving. DISTRONIC Active Proximity Control and Active Steer Assist now provide even more comfortable support for the driver to keep a safe distance and steer. The speed is now adjusted automatically ahead of curves or junctions. This is complemented by a considerably improved Active Lane Change Assist and additional functions of the Active Emergency Stop Assist.
What else? Well, a 'Remote Parking Assist' feature enables the car to be parked remotely using a smartphone app. The Burmester High-End 3D Surround Sound system now has even more speakers and an output of 1,520 watts. And a new Concierge Service can help the S-Class driver with everything from making restaurant reservations and obtaining tips about tourist routes, to gathering information on cultural or sporting events, before sending navigation destinations directly to the vehicle.
Fuel consumption is pretty much the same as it was in the pre-facelifted model. Choose an S350d variant - as we suspect most British S-Class customers will - and you'll get 52.3 miles from a gallon of diesel and 139g/km. Of course, if you choose conventional petrol power, your running costs will rise substantially. The S500 manages 40.9mpg and 157g/km. While the S 63 delivers 32.1mpg and 199g/km. The S 65 delivers just 23.7mpg and 279g/km. Helping the ore efficient variants is Mercedes' almost obsessive quest to reduce consumption and emissions. All of the S-Class body is fabricated from aluminium to cut weight for example.
It's worth knowing that your maintenance outlay can be kept in check by going for the optional Service Care package that takes care of routine maintenance, spreading the cost of regular servicing, guaranteeing the price of parts and labour for up to four services and covering the cost of all recommended service items such as brake fluid, spark plugs, air filters, fuel filters and screen wash. There's also an ASSYST dashboard service indicator that monitors engine use and tells you exactly when a garage visit is due.
This S-Class spearheads technological development, not only for Mercedes-Benz but for the automotive industry as a whole - and has done for decades. It's that important and is why this is - and will continue to be - the world's best selling luxury car.
In this improved sixth generation form, it can power to supercar speeds in AMG guise, deliver nearly 100mpg in Plug-in Hybrid form and can be specified to eerily steer, power and brake itself at a cruise in whatever form you decide upon. Magic Body Control can even make bumps and potholes disappear, transforming the roadway into a magic carpet. No other car you could choose can do all of this, which is why this S-Class will remain a benchmark for the kind of luxury saloon every prestige brand would like to build and a reference point for the current state of automotive technology. The best car in the world? You'll feel like it is if you buy one.