BMW M5 M xDrive M Steptronic vs. Mercedes-AMG E63 S 4Matic+ 9G-tronic: two executive sedans at the top of their respective games compete for a seat at the head of the boardroom table...

Asked at the recent Geneva International Motor Show who he felt AMG’s biggest modern-day rival was, head of Mercedes-Benz’s performance division, Tobias Moers, paused momentarily before proclaiming it to be Porsche. Granted, this was moments after the reveal of the Panamera-targeting AMG GT 4-door. And, yet, with the ink barely dry on myriad comparison tests between 911 and AMG GT coupé – and amid plenty of talk about the performance potential of the Formula One-inspired Mercedes-AMG Project One in relation to the suitably sophisticated 918 Spyder – Mr Moers would have been only too aware of the glare across the hall from an altogether more familiar foe.

While the exploits of the mighty Mercedes-AMG E63 S have been well documented over the past 12 months (including a top-three finish in Performance Shootout 2018), its biggest challenge was always likely to come from an all-new BMW M5. And never before have these two been so evenly matched.

Design and packaging

Each based on the latest generation of BMW and Mercedes-Benz’s impressively competent executive sedans, it’s interesting to note the design directions the brands have adopted with their newest super four-doors. Granted, Mercedes-Benz SA sells only the more powerful S variant of the E63 in SA – the more powerful 460 kW/800 N.m M5 Competition Package is due to arrive in the fourth quarter of 2018 – but, parked alongside one another, it’s the AMG that looks the more muscular.

While bonnet bulges and inflated wheelarches are par for the course in this league, you do get the sense BMW, with its optional 20-inch alloy wheels (19s are standard) and a colour palette that runs through various shades of grey to this distinct Snapper Rocks Blue metallic, allows owners to decide how much of a statement their M5 should make. The carbon-fibre-reinforced-plastic roof and M-specific side mirrors, however, are subtle clues.

By contrast – and even in this understated white – the E63 S looks menacing from most angles. If its V-shaped bonnet bulges and bespoke front spoiler don’t signal sufficient intent, the standard 20-inch alloys and collection of chrome tailpipes protruding from the rear certainly drive home the point: there’s nothing subtle about the most powerful E-Class to date.
>Complete with backlit badging in the headrests, the M5’s beautifully crafted front seats may look like they had a design department of their own, but it’s the rival Affalterbach-made items that offer a marginally superior range of movement and adjustment in relation to the steering wheel. That said, the BMW’s slightly raised driving position soon feels familiar.

As a pivotal point of contact in the cabin, both Mercedes-AMG and BMW M GmbH know how to craft the look and feel of a steering wheel. While the superbly weighted transmission paddles mounted to the Benz’s wheel claim pride of place, the BMW’s slightly smaller paddles are supplemented by a shiftable transmission lever the AMG does without. A highlight of the BMW’s steering wheel is the two red driving-mode switches that access pre-configured performance settings.

While CAR’s testers rated both cabins equally highly in most aspects, from ergonomics to aesthetics, the M5’s interior felt the sturdier of these two particular test units. Yes, this E63 S has 13 000, likely hard, kilometres under its belt, but this is but one of a number of Mercedes-Benz products we’ve tested lately that have exhibited some fragility in terms of build quality. There were, for example, distinct rattles emanating from the dashboard; something we noticed on the E63 S that took part in Shootout, too.

Drivetrain

At this year’s Geneva show, Audi also unveiled its new A6 range, which will eventually spawn an RS6. And, a little awkwardly, on the other side of the same Hall 1, the person responsible for the most recent developments of the legendary Quattro all-wheel-drive system was fielding questions about his new role as CEO of BMW’s M division. It wasn’t until Frank van Meel arrived at BMW in 2015 that the idea of an all-wheel-driven M5 was taken seriously. And, yet, following in the tyre treads of the latest E63 S, the sixth-generation (F90) M5 is fitted with the company’s fully variable M xDrive system.

Like AMG’s 4Matic+ system, M xDrive channels the bulk of available torque to the rear wheels until its highly intuitive ECU decides how much twist is required up front to maintain an acceptable level of poise. As per the Benz’s system, a variety of driving modes (including completely RWD) is available depending on both mood and driving conditions. Ironically, given the rear-wheel-drive legacy of these brands, there’s a better all-round driving experience, including a welcome element of tail-wagging playfulness, to be had with both axles remaining online.

At the peak of their respective super-sedan games, both the M5 and the E63 S deliver power and torque figures capable of defying the odds when it comes to shifting close to two tonnes. While the twin-turbocharged 4,0-litre V8 in the Mercedes offers 450 kW and 850 N.m, the 4,4-litre twin-turbo V8 in the M5 delivers 441 kW and 750 N.m. The AMG is driven via a nine-speed automatic, while the M5 boasts an eight-speed torque-converter automatic (replacing the previous car’s dual-clutch). The Munich contender makes up for being down on power and torque by weighing 178 kg less.

Performance

“Simply staggering”, to quote one of our testers. Apart from the obvious advantages all-wheel drive brings to these packages, a further benefit is the ability to launch each car from standstill without the need to carefully manage rear tyres scrambling for grip. Using launch control in both, the AMG recorded a best 0-100 km/h time of 3,40 seconds flat, with the BMW a whisker behind at 3,43 seconds. On the move, the Mercedes-Benz was able to accelerate from 40-120 km/h in 3,74 seconds, with the M5 arriving just 0,01 seconds later.

The lighter BMW made the best of its optional (R128 200) carbon-ceramic brakes to stop from 100 km/h in an average time of just 2,81 seconds, while the heavier (2 093 kg) AMG, fitted with steel discs, stopped marginally slower, averaging 2,92 seconds. Despite the M5’s heavier claimed fuel consumption, it was slightly more frugal on our 100 km fuel route.

Ride and handling

With lap times for both cars within a fraction of each other and given how closely matched they are in terms of performance figures, you’d expect these rivals to deliver similar driving experiences. Far from it.

Much like its toned-down styling, there’s a decidedly grown-up, less brash demeanour offered by the new M5. From its impressively supple ride in comfort mode, to a muted exhaust note compared with that of the AMG, there’s a clearly defined wolf-in-sheep’s-clothing character to the car. That makes the M5 easier to live with on a daily basis. While the BMW’s vast choice of driving modes and system configurations may initially seem daunting, what those aforementioned red pre-set buttons offer are shortcuts to your favourite settings: one tame and the other race-ready.

From start-up, the E63 S makes no apologies for being an aggressively tuned sedan. It’s not to say the AMG isn’t similarly capable of performing commuter duties; it’s just that you’re aware that there’s someplace less congested where the car would rather be. Despite sitting on air springs, the E63 S’ ride quality can’t match the suppleness of the BMW’s. Its firmer edge does, however, suit the car’s character. Where the M5 feels like an executive sedan capable of going very fast, the E63 S creates the impression of a very fast car that’s just about content performing executive-sedan duties.

In their raciest settings, the BMW is lighter on its feet. The AMG, on the other hand, feels the larger car on the road, which makes the level of poise and balance it displays that much more impressive. Along with the guttural bark of its exhaust note, the E63 S implores you to get in and go … in a hurry. Unlike AMG-tuned products of yore, however, the wonderfully sorted all-wheel-drive system adds a welcome – yet not restrictive – safety net.

The M5 counters that exhibitionism by being more clinical and precise, and will arguably deliver a more rewarding driving experience the longer you spend learning and appreciating its finer points. With its impressively intuitive M xDrive system, BMW appears to have stolen a march on its four-ringed rival whose reputation is built on all-wheel-drive mobility. Capable of handling like a rear-wheel-drive car when it matters, the advantage of the BMW’s fully variable system, together with its 100% lockable rear-mounted differential, is that there is almost no situation in which the driver needs to do anything other than accelerate, brake and steer in order to maintain impressive pace.



TEST SUMMARY

Two bouncers stand outside a nightclub, monitoring security. The scowling one on the left wears a suit with seams struggling to rein in the brawn beneath. The grinning one on the right has a suit better tailored to his leaner, more athletic physique. But you wouldn't want to be removed from the club by either, would you? Both look likely to inflict damage in their own particular way.

What's most impressive about both the AMG and the BMW is not necessarily the ease with which they are able to shift their respective two tonnes of executive-sedan bulk, but rather the way their makers have embraced the need for a change in thinking in how all that power is transferred to the road. Certainly, if you're Audi, you must be wondering how AMG and BMW have managed to create systems so quickly that continuously transfer torque to both axles without diluting driving dynamics.

While there's virtually nothing separating the E63 S and M5 in terms of performance, the CAR team voted in favour of the BMW because of its superior ride, better perceived build quality, more fluid everyday driving manners and the matter of a R130 000-ish price gap. That's not to say we won't still instantly swing our heads round at the first hint of an E63 S at full cry.

*From the June 2018 issue of CAR magazine

ROAD TEST SCORE

E-Class Mercedes-AMG E63 S 4Matic+
82 / 100
  • Price: R2,051,413
  • 0-100 km/h: 3.4
  • Power ([email protected]/min): 450 KW @ 5750-6500
  • Torque ([email protected]/min): 850 N.m @ 2500-4500
  • Top speed: 250 (opt 300)
  • Claimed cons. (l/100 km): 10.8 l/100 KM's
  • C02 emissions (g/km): 245 g/KM