Speed Week 2017: E63 AMG vs Audi RS3 vs BMW M4 CS

Merc's almighty four-wheel drive E63 takes on the dinky RS3 and the hardcore M4 CS

Sun and rain. They had a big effect on the cars we have here. When the clouds gathered, the rain fell and the track darkened, I thought one was a revelation, another a total liability.

When the sun shone, the wind blew and the track dried, those positions were reversed – one danced, the other dulled. The third car? Well, that wasn’t fazed by anything at all.  

Words: Ollie Marriage

Sensible representatives of the German big three. Who’d have thought they’d deliver anything other than a perfectly polished performance? But here’s the thing – each of these has a very strong character, a certain way of doing things that colours the way it drives as well as the conditions it thrives in.

They’re not direct rivals. They don’t sit in the same class. We’re calling them the super-saloons, but one’s a hot hatch, another a coupe. One’s rear-wheel-drive, one’s 4WD, the third is, well, both.

Let’s start with the Audi RS3. It’s the new saloon version, with 33bhp more from the single-turbo 2.5-litre 5cyl, new 4WD software and benefitting from an aluminium crankcase and magnesium oil pan, which help remove 26kg from the front axle. It’s a potent, dense little car, a mobile wrecking ball.

In its sights, the BMW M4 CS. Welcome to the squeezed middle of the M4 range: above the everyday model, below the daft 700-only two-seat, 500bhp £120,770 GTS. This is different: most of the learnings from the GTS, shoe-horned into a regular bodyshell. With a curvy carbon bonnet and a £90k sticker price. Hmm.

Which makes the M4 CS £640 more expensive than the Mercedes-AMG E63S. You can have a non S for about 10 grand less, but you need the S. Need it. Switchable 4WD, an extra 41bhp and 73lb ft, bigger brakes, dynamic engine mounts and a cleverer rear diff. AMG terms that switchable 4WD system Drift Mode, and it’s only accessible if you take all settings to Defcon 1 and disarm the stability control. Sounds sensible.

It’s raining, it’s our first laps at Knockhill and I’m in the RS3. Of course I am. You need an Audi for exploratory laps because it’s safe, stable and will categorically not do anything ‘exciting’. Two laps later: What. A. Weapon.

It’s so fast. That five-cylinder howl, the DSG punch, the traction, front-end bite, positive steering. I’m genuinely chuckling along. I expect the lightened nose makes a difference, but I bet fitting wider tyres front than rear (255 plays 235) makes a bigger one. I reckon it’s the fastest thing out here right now, so with confidence gained I switch to the M4 CS.

Evil, evil thing. OK, it doesn’t help that it’s wearing Michelin Cup 2 track-focused tyres, but I thought there’d be some progression as it broke away, some sensitivity. But the back end moves around as alarmingly as the madly flapping windscreen wipers, the turbos spike and fizz, the chassis skitters, I get the jitters…

It’s with considerable trepidation I crawl out of the pits in the E63, but, like the RS3, this is a car that dominates the conditions rather than being subverted by them. It relishes the rain, pushes weight and momentum through the puddles and has a 4WD system that’s genuinely rear-biased.

Audi says its 4WD system is, too, but the best you find is clean neutrality. In the Merc, at the point you pour on power and expect to push wide, you find the torque flow being diverted to the aft axle, the line tightening, the speed building and you’re off, away down the next straight much sooner than you anticipated. Three hundred extra kilos takes a little more control, but the brakes, the steering, the confidence you build behind the wheel of this big exec are remarkable.

Knockhill has its own weather system, so ten minutes later, the track is dry. I head out in the E63 again to see if it can repeat the handling feats it managed in the wet. It can. How can any car, let alone a tall, fully kitted-out saloon weighing almost two tonnes, be so positive, so tight on circuit? It’s rampantly fast, sounds bloody awesome and never feels less than dramatic and exciting.

Back to the RS3 to see if it can raise its game, too. Ah. No. It’s a one-trick pony. The trick (getting around a treacherous wet circuit or along a difficult B-road at unfeasible speed) is a good one, but the RS3 does the same thing at every corner of any radius.

You put an input in and hold it until you come out the other side, howlingly fast and mostly straight, but you’re slightly puzzled to realise you’re still holding on to a quarter of a turn of lock. The RS3 is a good fast road car, but not a handling hero. Way better than the RS5, though.

The M4 CS goes from zero to hero. Where in the wet it was snatchy, in the dry it’s tactile, sensitive, a wonderful communicator. There’s no slack, yet it’s beautifully damped, adjustable, a charger and everything else we want an M4 to be. Personally, I’d like it with two more doors and £30k lopped off the sticker price, but the supremely adjustable CS does throw a revealing light on the one-dimensional RS3.

Rapid it might be, but dynamically the Audi surfs in the shallows of this group. Both are forced to look up to the Mercedes-AMG E63. I don’t think there’s ever been a super-saloon that has looked so dominant in its class. It’s the winner.

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