Mercedes-Benz SL-Class vs Mazda 6

What's the difference?

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.

So, what did my family think about the Mazda6 20th Anniversary wagon? Firstly, I like that it drives well and how many luxe features are up front. The trims and body paint look divine but there's a disconnect with family practicality in the back seat. Besides the multimedia system, which 100 per cent needs to be improved, I don't mind the retro-feeling elements in the cockpit but my husband's first comment was that it looked old.

It may be better suited to a smaller and older family that isn't carting around a stack of gear but you get a lot of features for your cash in this model. So, this gets a 7.0/10 from me.

My son didn't spend heaps of time in this one but he liked the colour of it and the seats. He gives it a 7.0/10.

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.

At first glance there's not a lot that separates this from its siblings, it's not until you get up close that you notice more shiny chrome accents on the grille, those special anniversary badges on the side and its limited colour options – I hope you like red or white, as those are your only choices!

The wagon manages to look sporty with its 19-inch alloy wheels, full LED exterior lights and the classic protruding nose that Mazda seems known for now.

It's far more obvious in the interior though with the beautiful tan Nappa leather seats, synthetic suede trims and special embossing on the front headrests.

Surprisingly, the dashboard is still headlined by the older 8.0-inch touchscreen multimedia system. There's also the traditional gear-shifter and buttons/dials to deal with. All of which manage to nod to its long history while starting to feel like relics for such a special edition.

Overall, its pleasant and handsome but don't expect to be wowed, Mazda hasn't broken new ground with this one.

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.

The interior is comfortable and well-proportioned but front passengers will enjoy the most room. You'll still feel like you'll be jostling for premium armrest position, though!

Up front, the individual storage is adequate and the open utility tray is large but my phone slid around in it, making it hard to use the wireless charging pad.

There are enough charging options throughout the car to satisfy four people, with two USB-A ports in each row. Curiously, you can only utilise the backseat USBs when the armrest is down, which makes this feel more suited to a smaller family.

The 8.0-inch touchscreen is small and the graphics aren't super clear. You can use it as a touchscreen or opt for the rotary dial but I found switching between the two awkward. Especially, since the touchscreen is disabled while using the (wireless) Apple CarPlay or (wired) Android Auto.

The back seat is quite lean when it comes to amenities and storage. Although, the heated outboard seats are a nice touch, but again, you can only access the controls when the armrest is down.

You can fit up to three (skinny) child seats but with the low roofline, you might not want to be bending over to buckle them in.  The door apertures are not too wide either but my six-year-old had no trouble climbing in and out.

For this class, the boot is an okay size at 506L. There is a temporary spare wheel under the level loading space and it's great how the cargo-blind lifts up and away from the space because it's attached to the boot lid.

Unfortunately, this doesn't come with a powered tailgate and I did miss having that feature this week.

As the name suggests, this is a special edition and it bumps the Atenza from its usual 'top spot' in the model line-up. Yet, for a top-model it is spectacularly well-priced at $54,935, before on-road costs.

That places it below the Volkswagen Passat 162TSI Elegance ($57,190) and above the Skoda Octavia RS 180TSI ($53,090) wagons.

You get all of the features of the Atenza, like the luxurious heated and ventilated front seats, heated rear outboard seats, heated steering wheel and a sunroof.

Then, you'll also be enjoying the 20th Anniversary badging on the exterior, tan Nappa leather seats with that same badging embossed on the headrests and a delightful synthetic suede trim on the dashboard.

Other features include some nice tech, like wireless Apple CarPlay and wired Android Auto, dual-zone climate control and a premium Bose sound system with 11 speakers, but more on tech below.

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.

This shares the same engine with the Atenza and that's a 2.5-litre, four-cylinder turbo-petrol one. It has a max power output of 173kW and 420Nm of torque. Plenty of oomph to get you (and your gear) to where you need to go.

The 20th Anniversary edition is a front-wheel-drive and has a six-speed auto transmission. It's not the smoothest combination at lower speeds but let it stretch its legs and you'll be happy with the results.

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.

Let's talk about efficiency. It has a combined cycle fuel figure of 7.6L/100km but I only managed to achieve 10.9L. I reckon that's pretty thirsty considering how much open-road driving I did this week but it's not outrageous for a turbo. Expect a higher figure in an urban setting.

Based on the combined figure, you should be able to get a driving range of around 816km, which is perfectly respectable for those wanting to do a road trip.

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.  

This is a car that knows what it is and stays in its lane. It's not trying to be the best but it certainly comes close with how it handles itself.

The lower centre of gravity and responsive steering make it hug corners and the car feels firmly situated on the road.

There's enough power that this is a comfy open-roader and you're confident overtaking or getting up to speed but you do feel like you're starting to dig when you hit steeper slopes.

The suspension is a little firm but your backseat passengers will feel that more than you will. Still, it absorbs enough of the bumps that you feel cushioned, even on rough country roads!

The cabin space is fairly quiet but you will get wind noise at higher speeds. Otherwise, all passengers should be able to chat without raising their voices.

I didn't find this to be a bother to park but the 360-degree view camera is terrible. It's very blurry and on the 8.0-inch screen, the image looks small, too.

That said, I love the 11m turning circle and the front and rear parking sensors. Overall, you won't have much trouble parking this one.

Safety is important on any car, but more so on a family one. I'm happy this has the usual specs, like daytime running lights, lane keeping aid, lane departure alert, blind-spot monitoring, rear cross-traffic alert, 360-degree view camera, front and rear parking sensors and intelligent seatbelt reminders.

I like the fact the adaptive cruise control now has a stop and go function and that traffic sign recognition and a head-up display are included.

The autonomous emergency braking (and forward collision warning) with car, pedestrian and cyclist detection, is operational from 10–80km/h (a little slower than the average 5.0km/h).

It has a maximum five-star ANCAP safety rating but it was done a while ago in 2018. It only has six airbags which is a bit low for a family vehicle now but that does include curtain airbags covering both rows.

There are ISOFIX child seat mounts on the outboard rear seats and three top-tether anchor points across the back. You may get lucky with three skinny child seats but two will fit best.

A 0-4 rearward facing child seat can be installed but will encroach on front passenger comfort, especially if they're tall.

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.

The ongoing costs match the purchase price for their affordability. This has a five-year/unlimited km warranty, which is pretty normal for this class.

However, on the five-year servicing plan, services average $501 per service - which is very competitive for this class! Servicing intervals are also reasonable at every 12 months or 15,000km, whichever occurs first.

You're not even getting hit with the fuel pricing you can see on other mid-range models because this accepts a minimum of 91 RON petrol and is even E10 suitable.