Denza B8 vs Mercedes-Benz SL63

What's the difference?

The Denza B8 is an incredibly luxurious car that has a lot going for it, including three rows of seating, a 3.5-tonne braked towing capacity and an eye-popping price tag, but it's held back by its overall heft and cumbersome ride.

If you don’t absolutely need the third row of seating, the smaller B5 is arguably the better pick and while it’s also not perfect, it’s a very compelling package and you’ll be saving thousands of dollars in the process.

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

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.

There’s no way around it, the Denza B8 is a big car. It’s almost 5.2 metres long which makes it larger than a LandCruiser 300 Series and more in line with the likes of the Land Rover Defender 130.

It looks quite boxy and tough on the outside, though it doesn’t have any features that define it specifically as a Denza beyond the inconspicuous badging. There are many angles that are reminiscent of the aforementioned Defender.

The body lines look crisper than the smaller B5, as does the semi closed-off grille and LED light script that connect the big LED headlights.

Unlike the B5, the tailgate-mounted spare wheel is much more prominent in the B8 and this therefore exaggerates its heft, not in a good way.

Inside, it’s luxurious and high-end with lots of visual appeal. I particularly like the amount of soft-touch finishes around the cabin and the overall lack of glossy piano black.

While luxurious, there’s also a rugged edge to the interior. This is most present in the large grab handles which you do need to use when getting in and out.

The amount of physical buttons and switches inside is a nice touch as you don’t need to relate on the touchscreen all the time. The fact the gear shift lever rises up when you turn on the car also adds to the special, luxurious feel.

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.

Hopping into the B8 you need to acquaint yourself with how the flush door handles operate. Generally they pop open when you unlock the car but sometimes they can be a little delayed.

Also inside the car there are electronic door release buttons which are nowhere near as intuitive as regular door pull handles. Sure you’d likely get used to this over time but you’ll need to explain it to new passengers all the time.

The seats in Chinese cars usually look nice but aren’t that comfortable or supportive for long-distance journeys. The B8’s are the opposite, offering great support and almost limitless adjustability. Adding to this is the standard heating, ventilation and massage functions.

Ahead of the driver is a leather-wrapped steering wheel which feels nice and has plenty of physical buttons with a tactile click when pressed.

Behind this, the digital instrument cluster is clear and high-resolution and offers a number of different layouts and informative pages you can cycle through. This allows you to customise the display.

In the centre of the dashboard is the mammoth 17.3-inch touchscreen multimedia system which is the largest central screen I have seen in a car to date. It’s a big screen for a big car and Apple CarPlay satisfyingly takes up the entire screen.

Thankfully, the screen is snappy and has a native user interface that is easy to navigate around without getting lost. I particularly like the swipe-down control centre menu that allows you to change key settings without diving into sub-menus.

My only hassle with the screen is I struggle to reach the far left-hand side due to its overall size. Perhaps a trackpad would solve this.

As I noted previously, the amount of physical switchgear around the cabin makes adjusting key functions easy. Examples include physical buttons to change the drive mode, activate the surround-view camera, adjust the suspension position and switch between EV and hybrid driving.

In terms of storage up front there are two non-ventilated 50W wireless phone chargers, two cupholders with adjustable depths, a shallow storage section under the centre console, plus a fridge/hotbox under the centre armrest.

Moving to the second row and the luxury continues. The seven-seat model features a three-seat bench that three people can easily fit across as the floor is flat, whereas the six-seat model gets uber-plush captain’s chairs.

Regardless of variant, there’s plenty of room in the second row, even for adults.

Second-row amenities include a small screen on the back of the centre console box that allows you to change the climate control and change the seat heating/ventilation, among other functions.

There’s also a button that opens the fridge/coolbox so the second-row passengers can access it. This is a nifty touch though you’d want to make sure small fingers don’t get caught as the anti-pinch function isn’t the strongest.

A feature that’s unique to the six-seat version is a massaging function on the second-row captain’s chairs. This is a very cool touch that no other SUV at this price point offers.

Accessing the third row in the six-seat version is rather easy as you only need to walk down between the captain’s chairs. It’s also simple enough in the seven-seat version as long as you access it from the kerb side.

Third-row space is decent for adults, but this shouldn’t be surprising as the B8 is such a hulking vehicle. The backrests also recline allowing for extra comfort. Amenities include air vents in the headliner, USB-C ports and scattered storage. It’s enough for seats that will likely only get occasional use.

Around the back the B8 has a side-hinged tailgate which is a little problematic as you need to allow space for it to open up in parking spaces. This is hard when the car is already 5.2m long…

With all three rows upright there is 147L of boot space, which is fine, but this expands to a much more usable 920L with the third row folded.

The boot space is square and usable, though there is a large load lip which is body-coloured and would easily get scratched if you drop something on it. Not the best in a family-oriented vehicle.

Boot-related amenities include buttons to electronically fold the second and third row seats and lower the suspension to make things easier to load into the boot, a 12V socket, scattered hooks, as well as a small underfloor section to store the changing cables.

Although it stands out like a sore thumb, it’s great to have a full-size spare wheel on the back of the tailgate. This is very helpful in the unlikely and unfortunate event you get a puncture.

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).

Power comes from a plug-in hybrid set-up combining dual electric motors and a 2.0-litre turbo-petrol four-cylinder engine.

Total system outputs are a meaty 425kW and 760Nm. They need to be, as the B8 has a kerb weight of 3.3 tonnes. Despite this, Denza claims it can still do the 0-100km/h sprint in just 4.8 seconds.

Power is sent to all four wheels with a rear mechanical diff lock as standard across the line-up. A front diff lock is only offered on the six-seat version.

What’s most surprising about this big beast is it offers a segment-meeting 3500kg braked towing capacity. It also has up to 700kg of payload, depending on the variant.

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.

Feeding the dual electric motors is a 36.8kWh lithium iron phosphate (LFP) battery. Denza claims it allows for an electric range of 115km, according to NEDC testing.

The battery can also be used as a power source for appliances using vehicle-to-load (V2L) functionality at rates up to 6.6kW.

AC charging is offered at rates up to 11kW, whereas DC fast-charging is offered at rates up to 120kW.

Additionally, there’s a 91L fuel tank. Denza claims this allows the B8 to have a total range of 1040km (NEDC).

Fuel consumption depends on how often you charge the battery. Denza claims the B8 will use 2.0L/100km from 100 to 25 per cent battery charge and 9.9L/100km under 25 per cent battery charge, both according to NEDC testing. Regardless, this is better than all similarly sized petrol- or diesel-powered SUVs.

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.

Behind the wheel, the Denza B8 primarily acts as an electric vehicle (EV), meaning it’s largely quiet inside the cabin when driving around normally.

Once the battery charge gets down lower, the petrol engine typically switches on to top up the battery. It largely acts as a generator and a lot of the time you can’t tell whether it’s on or off.

You’ll likely only notice it if you floor the accelerator or go up a steeper hill. Even then the engine largely stays quiet and in the background.

When the battery charge gets down low enough and you gun it, the petrol engine can directly power the front wheels. This is rare, though, because the car leaves at least 25 per cent battery charge in reserve.

With 425kW and 760Nm thanks to the dual electric motors and 2.0-litre turbo-petrol engine, the B8 is far from slow. In fact, for a 3.3-tonne beast it absolutely hauls thanks to the instantaneous torque the electric motors provide.

However in the standard drive mode there is a noticeable input lag from when you push the accelerator pedal hard and when the car starts accelerating. This is reduced in the 'Sport' drive mode.

Although the B8 may produce lots of power and torque, it feels its weight. When you accelerate hard it pitches back dramatically, much like the Jeep Grand Cherokee. It’s much more pronounced than in the smaller B5, but still smile-inducing.

As standard, the B8 line-up gets an adaptive hydraulic suspension system that is claimed to be able to self-level the car. Despite this, the B8 gets a considerable amount of body roll regardless of which drive mode you select.

Many Chinese cars have floaty, comfort-oriented suspension tunes over firmer and a more dynamic-feeling ride, and the B8 is no exception. It feels like a 3300kg+ SUV.

The kicker is, like many body-on-frame vehicles, the ride gets busy on harsher roads with more frequent bumps. As a passenger you get jostled about in the cabin.

The steering tries to disguise the overall heft of this SUV but as a result it can feel overly assisted and vague at certain points. Depending on the drive it either artificially adds or reduces resistance.

Unlike the related BYD Shark 6, the B8 gets diff locks and a low-range mode which uses a clutch pack on the rear electric motor to allow for more controlled, low-speed crawling.

The adaptive hydraulic suspension allows the car to be lowered down or lifted up. In its highest mode there is a 890mm maximum wading depth.

Interestingly, compared to the smaller B5, the B8 feels more sorted off the beaten path. Its added heft helps round off bumps more easily, plus there’s added momentum behind it.

Lastly, in terms of noise, vibration and harshness (NVH), the B8 is a very quiet car to drive. As I mentioned above, the electric-first nature automatically makes this a quiet car.

Surprisingly, given the B8 is a huge 3.3-tonne box on wheels, there is very little road and wind noise. It seems Denza has put a big emphasis on sound insulation.

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 Denza B8 is covered by a six-year, 150,000km warranty, whereas the battery pack is covered by an eight-year, 160,000km warranty. There’s also three years of roadside assistance.

This isn’t a standout warranty in the mainstream market, though compared to premium marques it’s a notable step up.

Logbook servicing is required every 12 months or 20,000km, whichever comes first.

The first five years' of servicing totals $3762, which averages out to just over $750 per service. This is just a tad more than the smaller B5, but it’s much cheaper than premium rivals.

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.