Audi R8 vs Mercedes-Benz SL-Class

What's the difference?

The Audi R8 V10 RWD and V10 Performance Quattro have their own personalities. I'm a big fan of the lower-powered rear-wheel drive car, but the Performance is the ultimate here with better brakes and that 330km/h top speed. Either way the R8 is a true supercar, but one that doesn't have to be driven gingerly as though something may break off.

The new Mercedes-AMG SL63 4Matic+ is guaranteed to turn heads for decades to come. But there’s enormous design and engineering substance underpinning this car’s undoubted good looks. Stunning performance, superb dynamics and top-shelf safety make this a powerhouse GT to be reckoned with.

Note: CarsGuide attended this event as a guest of the manufacturer, with accommodation and meals provided.

Lamborghini styling can look over the top, McLarens can sometimes appear delicate and fragile, and Ferraris seem to be everywhere, and even for me, begin to blend into one.

The R8, though, looks exactly how an Audi supercar should look – understated, tough and serious. Have you seen that Audi advert with the R8 on a dyno not wearing any pants? That sounds ridiculous but Google it because it sums up what the R8 is – a real car with a raw race car underneath, that's meant to be driven comfortably on the road and hard on a race track and the styling indicates that intent with little in the way of fanfare.

Well, there is that big window at the back which shows off the engine and the 'side blades' that surround the large vents carved into the side of the car to cool the engine.

The latest update has taken the design from the second-gen car which arrived in 2016 and added a new grille, front bumper, door sills and vents in the rear bumper. It's a more angular, sharper, and busier design with more vents and winglets than ever.

The R8 V10 RWD and R8 V10 Performance are close to identical in their styling. You can pick the Performance by its gloss carbon front spoiler, side sills, mirror caps and rear diffuser. The RWD has gloss black elements instead.

Which looks best: the Coupe or Spyder? That's a personal thing, but I reckon race cars need to have a hardtop roof, so it's the coupe for me, please.

Built using the 'Audi Space Frame' which weighs only 200kg, the R8 is 4426mm long and just 1240mm tall, but at 1940mm across it has a wide, planted stance.

Rather than a strict two-seater, this time around the SL adds the flexibility of ‘+2’ rear seating while the previous 'Vario’ folding hardtop has been binned, the new car returning to a traditional, electrically-folding and weight-saving (-21kg) soft top. 

Mercedes-Benz design chief Gorden Wagener started the new model’s development from a ‘clean sheet’ and Mercedes-AMG says “not a single component comes from the predecessor SL, or any other model such as the AMG GT Roadsters”. 

Always a subjective call, but I think this car’s proportions are just about perfect. The lengthy bonnet with its twin longitudinal ‘Power Domes’, raked windscreen and fat haunches create a wide stance and presence that’s almost impossible to ignore.

Aggression, as with the sinister headlights and 21-inch rims, is subtly combined with soft curves along the flanks and around the rear. Note the seamless door handles.

And it’s not all about aesthetics. Active aero has been integrated into the front apron and retractable rear spoiler. Plus the ‘Z-fold’ roof design does away with the need for a separate cover.

The interior is sub-zero cool with slick screens, an 11.9-inch display covering multimedia and a 12.3-inch unit for instrumentation ahead of the driver, being particular highlights.

Turbine-style air-vents at the leading edge of the split-level dash and alloy trim elements are a tip-of-the-hat to SLs past and the deft mix of large flat surfaces with complex curves oozes design confidence.

The R8 is a two-seater supercar and practicality isn't high on its 'to do' list with limited cabin storage in the form door pockets almost as small as my jeans pockets, two cupholders hiding under a trapdoor in the centre armrest, a hidey hole in front of the shifter containing a wireless charger and two USB ports and the glove box.

As for the boot – there are two: one in the nose with a 112-litre cargo capacity and another behind the mid-mounted engine with 226 litres.

Room for people, well you and a friend, is excellent. I'm 191cm (6'3") tall with a 2.0m wingspan and found the footwell deep and spacious, while head and shoulder room is also good.

In the context of a high-performance GT, practicality is pretty impressive.

At just over 4.7m long the SL is a sizeable machine and much of its lengthy (2700mm) wheelbase is devoted to making the driver and front passenger comfortable.

There’s plenty of space for that pairing and just enough storage to cope with the ‘things’ they’ll typically bring with them.

Door pockets offer enough room for a few odds and ends, although you’ll struggle with even a medium-size bottle unless you’re willing to lay it down horizontally along the top of the aperture.

A handy lidded bin between the front seats doubles as a centre armrest, there are two cupholders under a sliding lid in the centre console and the glove box is a decent size. 

Power and connectivity options run to four USB-C ports, a 12-volt socket and the wireless device charging pad.

Then there are the rear ‘+2’ seats, and Mercedes makes no bones about the fact they’re intended for occasional use only, even suggesting a 1.5m occupant height limit.

And there’s no doubt they offer a handy emergency seat or a fun kids’ zone. Just ask a Porsche 911 Carrera owner how much this kind of seating arrangement increases a sports car’s flexibility.

At 183cm I gave the back seat a crack, which meant sliding the front (passenger) seat way forward with the backrest close to upright. But I squeezed in, and there was just enough legroom for a person in front at the same time. 

With the roof in place there’s the added pleasure of cranking your head over to around 45 degrees. But it’s do-able! 

No storage, adjustable ventilation, or power back there. But that’s fair enough, especially given there are USBs available in the front centre storage box.

Boot volume is 240 litres with the roof up and 213 litres with it folded, which is enough for some light luggage, and not too shabby when you think a Toyota Corolla hatch offers up just 217 litres (with all seats up).

There’s a 12V socket in there, but don’t bother looking for a spare, in the event of a flat your only option is a repair/inflator kit.

Priced at $373,370, before on-road costs, the new SL63 4Matic+ will be battling top-shelf performance soft tops including (in ascending dollar order) BMW’s M850i xDrive Convertible ($307,100), the Porsche 911 Carrera GTS Cabriolet ($386,900) and even exotics like the Lamborghini Huracan RWD Evo Spyder ($422,606). 

Value for money is a relative concept in this part of the market, although equipment highlights include a head-up display (with augmented reality nav), 11-speaker, 650-watt Burmester surround sound audio, ambient lighting (choice of 64 colours), hectares of Nappa leather trim, dual-zone climate control, an 11.9-inch central multimedia screen (running Merc’s latest ‘MBUX’ software), 12.3-inch configurable digital instrument display and 21-inch forged alloy rims.

There’s also the ‘Digital Light System’ built around three high-power LEDs in each headlight, refracted and directed through 1.3 million ‘micro-mirrors’ to create a combined resolution of 2.6 million pixels.

The ‘Neck Scarf’ function is added to the top of the front seats to keep your neck and the back of your head warm as the temperature drops, the heated, ventilated and massaging front seats feature eight-way electric adjustment and three memories, there’s a heated steering wheel, Android Auto and Apple CarPlay connectivity, wireless device charging and more.

Worth noting the big 21-inch rims in a ‘10-twin-spoke’ design are standard issue with an alternate ‘multi-spoke’ pattern available as a no-cost option. 

But if all that’s not enough you can opt for ‘AMG Performance seats’ ($2490) which grip you even more securely but delete the massage function.

Or there’s the ‘AMG Night Package’ ($6990) which adds wheels in matt black (with “high-sheen finish rim flange”), darkened head- and tail-lights, an aero package, black badging, black radiator fins and interior trim elements in black chrome.

Then you can go the whole hog with the ‘AMG Carbon Fibre Package’ ($11,990) which brings the wheels in matt black, exterior carbon elements, carbon mirrors, carbon interior trim and a steering wheel in a combination carbon-fibre and Dinamica (synthetic microsuede).

There are two grades in the Audi R8 range – the entry-point R8 V10 RWD which has rear-wheel drive (RWD), and the R8 V10 Performance Quattro which has all-wheel drive (AWD).

Both obviously have V10 engines, it's a naturally aspirated 5.2-litre petrol unit (so no turbos here), but the RWD makes less power and torque at 397kW and 540Nm, while the Performance produces 449kW and 560Nm.

The V10 is mounted behind the driver's seat but ahead of the rear axle making it mid-engined car. The engine even has its own window and you can see it in there with its face pressed up against the glass.

There are two body styles as well – the Coupe and Spyder (convertible, roadster, just another word for a retractable soft roof). We'll get to the prices in the next section, but let's talk about the more interesting numbers such as top speeds.

The V10 RWD in coupe form can reach 324km/h and the Spyder can hit 322km/h while the V10 Performance Coupe and Spyder are both a smidge quicker at 330km/h.

Those are all go-straight-to-jail speeds in Australia, so if you're tempted to fact check my numbers then do it on a racetrack. Audi holds excellent track days – I've done them and you'll not only get to drive the R8 as fast as you can, the instructors will help you improve your advanced driving skills, too. Do it, it could save your life.

Acceleration from 0-100km/h is rapid – 3.7 seconds and 3.8 seconds for the V10 RWD Coupe and Spyder respectively, while the V10 Performance Coupe and Spyder can nail it in 3.2 seconds and 3.3 seconds.

The V10 engine has a cylinder-on-demand feature which can shut down five of the cylinders while cruising on a motorway, say at 110km/h. It's a fuel-saving system, but keep in mind this V10 loves petrol and lots of it – I've hidden that all the way down the bottom of this review.

Shifting gears in all R8s is a seven-speed dual-clutch automatic transmission.

This new ‘4Matic’ all-wheel-drive SL63 features AMG’s (M177) 4.0-litre twin-turbo V8, superseding the previous rear-wheel-drive SL’s similarly configured 5.5-litre unit.

Hand built by one AMG technician from start to finish, it produces 430kW (around 580hp) from 5500-6500rpm and 800Nm across a broad plateau from 2500-5000rpm.

It’s something of a mechanical masterpiece, and the previous seven-speed auto transmission, driving the rear wheels only, has been replaced by a nine-speed dual-clutch auto (with wet multi-disc start-off clutch) sending drive to all four wheels via Merc’s ‘4Matic’ AWD system.

That's like asking how many calories are in this pavlova that I'm about to push into my mouth? Seriously if you're asking then you shouldn't be eating it – or driving the R8.

But just for the record, according to Audi the RWD R8 uses 12.0L/100km in Coupe form and 12.2L/100km in Spyder guise after a combination of urban and open roads, while the AWD R8 of course will use more at 13.4L/100km for both Coupe and Spyder.

Mercedes-AMG’s official fuel economy number for the SL63 on the combined (WLTP) cycle is 13.9L/100km, the 4.0-litre twin-turbo V8 emitting 319g/km of CO2 in the process.

On the roughly 300km launch program we covered urban, B-road and some freeway running, returning an (indicated) average of 17.5L/100km. And that reflects some enthusiastic driving along the way.

The fuel tank requires 70 litres of 98 RON premium unleaded to fill it which translates to a theoretical range of around 500km, dropping to 400km using our real-world number.

A race circuit is the best place to test the performance of an Audi R8. I've been lucky enough to have done this in the past, but for this update of the R8 the Australian launch was held on public roads and included a convoy of RS models such as the RS 6 Avant, RS 7, RS Q3 and TT RS.

Even then I think I was 'stitched up' because I began the day in the R8 V10 Performance Coupe but spent almost the entirety of my allocated time in roadworks at 40km/h before swapping to an RS Q3.

So, while I can't honesty comment about the dynamics on this updated R8 V10 Performance Coupe I can tell you that having driven every iteration of the R8 since 2012 that it's a weapon, with helicopter-like visibility out of that large front window.

If, like me, you think turbos are 'cheating' (superchargers are fine), then you'll love the linear power delivery of the R8's naturally aspirated V10, and while I love front-engined sportscars, nothing beats a mid-engined car for the feeling of balance and lightness in the nose while having the sound of thousands of explosions going off just behind your back.

Having AWD is not just great for acceleration and perfect traction from Audi's quattro system, I think it's a good safety feature in a supercar, and while only your judgements can stop things going pear shaped, the system will be there to help on slippery roads.

The following day was different. I was in the R8 V10 RWD, the country roads were superb and while it wasn't a racetrack it was enough to get a hint of the capabilities of the RWD R8.

While the R8 V10 RWD feels the same to sit in with the same great view, it feels different to drive than its faster sibling, in a good way. First there's the noticeable power difference – more than 50kW and 20Nm less – but also the lack of AWD makes the front end feel more pointable, and the car feel more like a traditional sportscar that pushes from behind rather than pulling from the front. Less power, but more fun.

The RS cars in our test convoy were all awesome machines, but stepping out of even the RS6 Avant and slipping down into the R8 cockpit was like getting into a UFO – it's so far ahead dynamically of any other Audi that all I could do was laugh like an idiot. Corners which were making an RS 7 really struggle, were handled effortlessly by the R8. And in a straight line it's a bullet in a barrel.

The Performance has the better brakes: 380mm ceramic discs with six piston calipers up front and 356mm discs with four piston calipers at the rear. The RWD has steel discs – 365mm with eight piston calipers up front and 356mm discs with four piston calipers in the rear.

Keep in mind if you are planning on track days, you'll find the ceramic discs costly to replace, and beside the stopping power of the steel ones is excellent.

And yet, on pot holed course bitumen the ride is a lot more comfortable than you might think and having driven the Performance in traffic it's a much nicer place to sit than the claustrophobic cabin of a McLaren 570S. You could honestly use the R8 daily.

I recall driving the AMG SL65 around the backroads of Tassie a few years ago and that twin-turbo V12 monster famously packed 1000Nm of torque, while this car ‘only’ has 800.

But there comes a point where enough is enough… and this is enough!

With maximum torque available from 2500-5000rpm and peak power (430kW) on call from 5500-6500rpm there’s always stupendous acceleration available with a squeeze of your right foot.

Claimed 0-100km/h time is supercar fast at 3.6 seconds, while top speed is a toupe-troubling 315 km/h. And that’s electronically limited!

A typically ferocious engine noise and howling exhaust note accompany rapid progress and shifts from the nine-speed dual-clutch transmission are quick and positive, not to mention especially enjoyable using the steering wheel-mounted paddles.

There are six ‘AMG Dynamic Select’ drive programs from Comfort through to Race, the latter including a Drift Mode, which we didn’t experiment with. Nor did we dip into the ‘AMG Track Pace’ system for circuit-focused mapping and timing

However, far from drifting, the grippy Michelin Pilot Sport 4S rubber (275/35 fr - 305/30 rr) plants the car securely with the all-wheel-drive system and electronic locking rear diff playing their part.

I found the perfect set-up was in the ‘Individual’ mode with the engine, transmission and steering in racier settings and the suspension in ‘Comfort’. The adaptive damping in this configuration mixes smooth ride compliance with sharp dynamic response.

The car’s aluminium space frame chassis is part of a body structure mixing aluminium, magnesium, fibre composites and various strength steels.

Torsional rigidity is claimed to have been improved by 18 per cent and despite the lack of a roof the SL feels tight and solid.

Suspension is by alloy double wishbones front and rear with adaptive damping and active hydraulic anti-roll stabilisation standard (so, no physical anti-roll bars).

At the same time the 4Matic AWD system is able to vary torque distribution up to 100 per cent to the front or rear axle depending on where drive can be put to best use.

The speed sensitive, variable ratio, electronically controlled steering is accurate and turns in beautifully with good road feel. No doubt assisted by electric rear steering able to adjust the angle of the rear tyres by up to 2.5 degrees.

All this adds up to a hugely impressive package that, despite its 1970kg kerb weight, feels agile, athletic and able to attack corners like an overgrown hot hatch, putting its power down with unwavering authority.   

While indecently fast the SL63 can also stop rapidly with the AMG high-performance braking system standard. 

Huge composite ventilated and cross-drilled discs (390mm fr - 360mm rr) are clamped by six-piston fixed alloy calipers at the front and single-piston units at the rear. They wash off speed calmly and consistently with perfect pedal feel.

Even at highway speeds, particularly with the windows up, normal conversation is easy with the roof down. But if you need to raise (or lower) it, the operation takes 15 seconds and is possible up to 60km/h. 

Under the heading of miscellaneous observations, the turning circle is a not insubstantial 12.8m, so beware in the car park.

A front axle lift function is a welcome standard feature, raising the car’s nose 30mm with the press of a button. And lift locations are stored in GPS data, so the car will subsequently remember to lift itself at the same place, even if you don’t! 

Heating and cooling for the front seats combined with the heated steering wheel and Air Scarf neck warming makes winter top-down driving a pleasure.

The digital instrument display is not only crystal clear, it can be changed through multiple configurations, including a tunnel-like graphic for engine revs as well as specific readouts for speed, g-force, the lot.

At the same time, the central media screen’s angle can be adjusted to better cope with reflections and the windscreen wiper system Merc calls ‘Magic Vision Control’ channels fluid along the wiper arms onto the rubbers, which isn’t new, but works spectacularly well here.  

No independent ANCAP safety assessment at this stage but the SL63 is fitted with the ‘Driving Assistance Package Plus’ which includes a heap of active (crash-avoidance) tech including AEB (with pedestrian detection), active cruise control, lane keeping assist, lane change assist, traffic sign assist, ‘Active Traffic-assist’ and ‘Active Steering Assist’. 

There’s also tyre pressure monitoring and the ‘Active Parking Assist with Parktronic’ self-parking system supported by a 360-degree camera view and multiple sensors. 

If a crash is unavoidable the airbag count runs to eight, including side bags for rear occupants. There are ISOFIX anchor points for child seats or baby capsules in the two rear and front passenger seat positions. And an active bonnet is designed to reduce injuries in the case of a pedestrian impact.

The R8 is covered by Audi's three-year, unlimited kilometre warranty which not only falls behind in duration compared to mainstream brands but also its direct rival Mercedes-Benz which now has five-year, unlimited kilometre coverage.

Service intervals are every 12 months or 15,000km but unlike other Audi models there isn't a three-year or five-year plan available.

The SL63 4Matic+ will be covered by Mercedes-AMG’s five-year/unlimited km warranty, with roadside and accident assistance included for the duration, both of which are expected in this category. 

Maintenance intervals are 12 months/20,000km, and a fixed-price service plan lists an average of $1583 for each of the first three visits to the workshop. Not exactly small change, but not unheard of in this part of the market.