Kia Optima vs Mercedes-Benz C43

What's the difference?

If you travel long distances, want a good amount of space and don’t want to pay big bucks for a new car, then yeah, maybe there is a reason sedans like this will hang around for a while longer.

Sure, the appeal of sedans mightn’t be as strong as it once was, but models like the Kia Optima prove they still have a reason to exist.

The new AMG C 43 may lack the drama and excitement we’ve come to expect from the German performance brand, but that doesn’t mean it’s a bad car. Yes, it could be more extroverted and the ride could be improved, but this is still a sharp-looking sports sedan with loads of punch.

This is a car that speaks to its times, with ever-stricter emissions regulations making it harder and harder for car companies to produce loud, wild and charismatic cars. So Mercedes-AMG has worked within those boundaries and come up with a car that retains at least some of those core elements that has made the brand so desirable over the years.

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

Cosmetic changes for the facelifted 2018 Kia Optima include new headlights and tail-lights with revised LED signatures (but still halogen lamps in the base model), and there are newly sculpted bumpers and new wheel designs across the two-model range. 

We had the base model Si, which doesn’t look as good as the GT model, because it has smaller wheels, the sporty body kit and misses out on the LED headlights, but the LED daytime running lights are still present.

The GT has a more aggressive look, and the side skirts, front spoiler and rear diffuser fit it better - there are dual exhausts, but not sporty quad exhaust tips.

In fact, this model is a bit like the old-man version of the Optima. No offence intended to old men, of course. The GT is just heaps sportier, and I reckon it’s considerably more attractive as a result. 

Still, the inherent sleek styling of the Optima remains - the chrome highlighting along the window line is a bit too sheeny for me, but the angles and stance of this model are quite gracious. I really dig the fact the top of the windscreen mirrors the ‘Tiger Nose’ grille shape.

I'm no exterior designer, but I liked the existing Optima more - it just looked a bit neater, even though it had a decent amount of bling with its Mercedes-like diamond-pattern grille, as opposed to the cheese grater look seen here.

There’s not quite as much bling inside the cabin of the Si, either, but it is still a well-designed space - just not as special as the premium package offering of the GT (which gets leather trim - not nappa leather, but still a quality cowhide finish, and more). Check out our interior photos to see if you agree - but size and interior dimensions of the Optima are hard to argue against.

Mercedes has created something of a problem for itself with its decision to introduce AMG styling packages for the majority of its range, including the C-Class.

It means the C 43 has to walk a fine line between looking like a unique AMG model, rather than just a C300 with a bodykit and not out-doing the C63.

To that end it has AMG’s now familiar grille with vertical bars, the unique and complex-looking 20-inch alloy rims and a small lip spoiler on the boot. But otherwise it is surprisingly understated for an AMG, lacking the more obvious and muscular stance of previous AMG offerings.

Inside, there’s a similar theme, with the typical Mercedes-Benz luxury appointments but with a sportier, AMG twist. The steering wheel is chunky and comes with AMG branding, metallic shift paddles and a pair of rotary dials/buttons that allow you to alter the various drive modes and settings.

The one on the right allows you to switch between the pre-set Comfort, Sport, Sport+ and Individual modes, while the one on the left can scroll between the various individual aspects to tailor the settings to the conditions.

In typical modern fashion the design is tech-laden, with a digital display for the instrument panel (that can be switched between various graphics) and a large, tablet-style central multimedia touchscreen that controls the majority of the car’s non-driving functions.

I really like the way Kia designs its cabins. Sure, there’s a lot of black in here, but there’s also a lot of thought put into the usability of the space.  

The high-mounted 7.0-inch infotainment and multimedia touch screen in the Si is simple to use, and for 2018 the Optima range gets Apple CarPlay and Android Auto - you couldn’t get that in the Optima up to this point. 

Also included are a reversing camera, USB input, Bluetooth phone and audio streaming and six speakers. The Si model misses out on sat nav - you’ll have to use the maps app on your phone. No DVD player either.

Storage is well thought out in here, with big bottle holders in the doors, a good sized pair of cup holders up front, and a nice little storage bin for your phone, wallet, keys and so on.

There’s a driver info screen with a digital speedo, and even on this base model you get a dual-zone climate control air conditioner. The updated Optima gets a new steering wheel, too.

Now, what about the back seat?

It may be considered a ‘mid-sized’ sedan, but there’s limo-like space. With the driver’s seat in my position (I’m about six feet tall) there was still heaps of rear legroom in the rear seat, with ample knee room, good foot room and decent shoulder space, too - three of me could slot across the back bench comfortably, which means kids will fit easily, too. There are three top-tether points and two ISOFIX points as well.

Kids and adults alike will be happy with the rear air vents back here, and there’s a flip down armrest with cupholders, too. Again, big bottle holders appear in the doors, and there are map pockets in the back seats.

What about boot space? With so many people choosing SUVs over sedans because they’re theoretically more practical, the Optima offers good food for thought - it has enough luggage capacity for a bunch of suitcases (510 litres VDA in size) and there’s a full-size alloy spare under the boot floor. If you need more, you could always invest in a roof rack setup?

The new C-Class has grown slightly in size compared to the model it replaces, most notably with a 26mm increase in the wheelbase which you can feel in the cabin.

The front seat space is good, with excellent adjustability for the power-adjustable seats and steering column. I had no trouble finding my ideal seating position which makes for a more enjoyable and uncompromised driving experience.

Rear space is a bit tighter (which is typical for this segment/size of vehicle), but thankfully the standard seats do have very deep sculpting in the backs which allow for more knee space and foot room.

However, at approximately 180cm (six-foot), I wouldn’t like to sit behind my seating position for long periods as my knees were touching the seat back, and headroom is compromised with the panoramic glass roof.

In terms of small item storage there’s a lidded console box in between the front seats as well as a pair of cupholders and a small tray where you can place your mobile phone.

It’s worth noting, though, that early examples of the C 43 in Australia do not have a wireless smartphone charging pad, with that reportedly being introduced from February production.

While that’s good news, it’s not really competitive in this day and age to offer a car costing six-figures without such technology.

There’s also only a single USB-C power outlet in the front, which is another disappointment, but there is a pair in the back.

Mercedes does win some points back for a respectable 455-litre boot, which has a nice wide load opening that will make packing luggage easier.

We’ll get to the major change under the bonnet shortly, but another significant alteration for this latest C 43 is the price.

It now starts at $134,900 (plus on-road costs), which pushes it well above its market rivals, the BMW M340i xDrive and Audi S4, which start at $104,900 and $106,200, respectively.

However, Mercedes has added more technology under the bonnet and loaded the C 43 up with standard equipment, including its '4Matic' all-wheel drive system, adaptive damping, rear-wheel steering and 20-inch alloy wheels.

In terms of creature comforts, the C 43 is well-appointed, with leather upholstery, a head-up display, augmented reality navigation, a panoramic sliding sunroof, and a Burmester 3D surround sound system.

There are two option packages for the C 43. The 'Digital Light Package' costs $2400 and adds Multibeam LED headlights with 'Ultra Range' highbeam, 'Adaptive Highbeam Assist Plus' as well as active light function and cornering light function.

The 'Performance Ergonomics Package' includes AMG Performance front seats, an AMG Performance steering wheel in Nappa leather and microfibre and the 'AMG Track Pace' system for an additional $5200.

The Si model is powered by a 2.4-litre four-cylinder petrol engine, which has seen no changes to its specifications for this mid-life update.

Engine specs remain at 138kW of power at 6000rpm, while torque is rated at 241Nm at 4000rpm. It makes use of a six-speed automatic transmission only - there’s no manual transmission here, but you do get paddle shifters - and it's front wheel drive (the Optima isn't available with AWD, or as a 4x4, or in rear wheel drive - the latter is left to its bigger brother, the Stinger).

The GT gets a zestier drivetrain with more horsepower - it has a 2.0-litre turbo four-cylinder engine with 180kW/350Nm, which is much more desirable, but also louder than the Si’s 2.4. It also has a six-speed auto transmission, and is FWD. If you're into ratings and statistics, that 2.0-litre with a turbocharger is one of the perkier offerings for its engine size in the class.

There is no hybrid model available, despite a plug in hybrid petrol version (allowing you to run in EV mode) being sold in European markets. No diesel here, either, while other markets get a 1.7-litre turbo diesel. No LPG model here, or anywhere else, for that matter.

Towing capacity for Optima models is 750kg unbraked and 1700kg braked for the 2.4-litre, and 700kg/1400kg for the 2.0-litre turbo. Tow bar down-weight is capped at 80kg.

If you're concerned about engine problems, suspension problems, clutch and transmission issues, be sure to check out our Kia Optima problems page.

The biggest talking point about this new car is the engine, with AMG downsizing from the old C 43’s six-cylinder to a 2.0-litre four-cylinder turbocharged petrol engine.

But it’s not just any turbocharged four-pot, because it is fitted with technology that Mercedes claims has been inspired directly from its Formula One team.

While the F1 team engine facility is based in England, this engine was designed and developed by the Mercedes-AMG team at its Affalterbach headquarters, but the concept of the electric turbocharger reportedly comes from the engine that powered Lewis Hamilton to multiple world championships.

The electric exhaust gas turbocharger - to give it its official name - uses a small electric motor on the turbocharger shaft to spin up the blades without having to wait for any exhaust gases to pass through it first.

To power the electric turbo the C 43 is equipped with a mild-hybrid 48-volt electrical system.

Mercedes claims this means reduced lag and improved throttle response for a sportier driving experience. 

It also helps make this small engine produce big amounts of performance, with AMG extracting 300kW of power and 500Nm of torque from this 2.0-litre, which is more power than the previous six-cylinder C 43 managed.

The engine is paired to a nine-speed multi-clutch transmission, which isn’t a dual-clutch with a pair of clutches operating on every second gear ratio, but instead uses a “wet start-off clutch” for better take-offs and smoother shifting on the move (at least in theory).

Power is sent to the road via all four wheels thanks to Mercedes’ 4Matic all-wheel drive system.

Kia claims a very realistic fuel economy rating of 8.3 litres per 100 kilometres for the Si model, and we saw damn close to that consumption during our week of testing. On the highway it will sit at around 6.5L/100km, ensuring good mileage, while city driving will push usage above 12.0L/100km. Our overall average was 8.5L/100km, which is good. Use the eco mode, and you'll get a little better use.

The turbocharged GT model uses a little more, according to Kia’s 8.5L/100km combined average claim, but we guarantee you’ll actually use more than that because it’s more eager to please.

Fuel tank capacity is 70 litres - plenty of size for long distance drives.

Despite the smaller engine you can hardly call the C 43 miserly, with a claimed combined urban/highway cycle rating of 9.1-litres per 100km. That’s only a 0.2L/100km improvement over the old six-cylinder.

On test, which included a return trip from Sydney to Bathurst via motorways and some dynamic back road driving, we saw a return of 11.8L/100km on the car's onboard computer.

While hardly hybrid-worrying, it’s impressive to think that driven modestly, such a potent engine can return a single-digit fuel figure.

The Optima has some really good elements to the way it drives, but sadly  some less impressive bits as well.

Let’s start with the not-so-great stuff - the 2.4-litre engine in this Si model just isn’t as enjoyable as the turbo unit, and the fact that Kia still doesn’t offer a hybrid version here, despite doing so elsewhere, is a bit of a downer.

The drivetrain isn’t terrible - the six-speed auto is smart enough, and there’s usable power if you boot it. The two more sedate drive modes, 'Eco' and 'Comfort', mean the transmission will aim to save fuel and limit throttle response, with a bit more of a lazy feel to the drive experience. But in 'Sport' mode it is definitely more rewarding in terms of acceleration and performance, offering a bit more pep and urgency (we didn't do a 0-100 km/h speed test, but take our word for it); it undoubtedly at the cost of fuel consumption.

It’s just a bit of a shame Kia doesn’t offer the turbo in this spec, too. Fuel use for the Si model is better than the turbo, however, so it could be ideal for buyers who are more worried about the bottom line than design and a sportier drive.

The thing I like most about the Optima is its road manners - the steering and suspension have been tuned for local conditions, just like all Kia products, and it shows. 

The electric power steering is really well sorted, making for easy parking moves and good assuredness at higher speeds. And the turning circle is decent, too - 10.9m (so, the turning radius is 5.45m). 

Plus the ride comfort is really good. On the highway it coasts along with very little fuss, and around town it deals with lumps and bumps impressively. Sharp edges can upset things a tad, and mid-corner bumps can make it jitterbug a little bit, but not to a degree that would rule it out of contention if you want a mid-sized sedan.

It’s pretty quiet on the open road, too, and the adaptive cruise control makes long-distance driving a simple task. The GT does suffer a little bit more road noise, though.

Let’s start with the good news. The new Mercedes-AMG C 43 is a quick car. The engine may be small in size but the electric turbocharger does its thing and provides plenty of punch.

You can get a performance boost, too, thanks to the belt-driven starter generator, which acts as a mild hybrid and gives you a surge of 10kW for a brief period if you need a sudden burst of extra speed.

The chassis is well-sorted, too, at least from a dynamic point-of-view. The rear-wheel steering can provide up to 2.5 degrees of turning, which improves handling at speed and manoeuvrability when parking.

However, there are some less-impressive elements to the C 43, too. The obvious one is the drama, or rather the lack thereof.

As I said at the beginning, the C 43 has never been as wild or raucous as the V8-powered C 63, but when you buy an AMG there’s a rightful expectation that it will provide some thrills.

The C 43 simply doesn’t have that character about it. Yes, it’s fast, but it produces that speed with efficiency rather than excitement.

And it’s not an engine size problem, because even the 2.0-litre four-cylinder A 35 and CLA 35 offer more ‘wow factor’ than the C 43.

Yes, the engine makes noise under acceleration (and it can be altered between discreet and sporty) but even at its best it sounds muted and lacks the evocative tone of a V8 or six-cylinder engine. 

Another disappointment is the transmission calibration, with the gearbox awkwardly shifting out of first gear on multiple occasions during our test drive.

In the taller gears it felt smooth enough cruising along, but given its low speed shifts we’d like to spend more time in the urban environment before passing final judgement. 

The other notable element of the driving experience we struggled with was the ride quality. While fine on the smoother motorways, our test drive included time on some patchy country back roads and the C 43, even in the ‘Comfort’ suspension setting, was simply too firm.

Riding on low profile tyres, the adaptive dampers struggled to isolate the cabin from the imperfections in the road, leading to a fussy ride at times.

Overall the C 43 is a good car, but it feels like there are still some areas where Mercedes could improve it to make it really live up to the AMG badge.

The C43 gets a comprehensive list of safety equipment that leaves little out. Obviously there are the usual passive safety items, like 10 airbags, including dual-front combined pelvic/thorax airbags and a front centre bag that drops between the front seat passengers to minimise the chances of a head clash.

Also included as standard is autonomous emergency braking front and rear (covering speeds between 7.0-200km/h), adaptive cruise control with active stop/go, a 360-degree parking camera, 'Active Parking Assist', 'Active Lane Keeping Assist', 'Blind Spot Assist' and, of course, anti-lock brakes with 'Brake Assist' and 'Adaptive Brakes' with Hold function and electronic stability control.

Also included are dusk-sensing LED lights, rain-sensing wipers and run-flat tyres with tyre pressure warning.

The C43 also comes equipped with Mercedes’ 'Driving Assistance Package Plus', which adds even more safety gear. This includes 'Active Blind Spot Assist', 'Active Brake Assist with Cross-Traffic Function', 'Active Emergency Stop Assist', 'Active Lane Change Assist', 'Active Lane Keeping Assist', 'Active Steering Assist', and 'Active Stop-and-Go Assist'.

While the C43 hasn’t been specifically crash-tested, the latest C-Class was rated by ANCAP with a five-star score for all models except the upcoming C 63 S E Performance.

Kia remains a shining light in terms of its new-car-ownership promise, with a very strong seven-year/unlimited kilometre warranty. It makes a lot of sense if you plan to hang onto the car for a while. There's no extended warranty available, which is understandable.

That plan also includes a roadside-assist plan for the same seven-year period, provided you maintain your car with Kia Australia. So, given you get one year to start with, then you get an extra year of cover every time you go back to Kia to get your car serviced, you could end up with eight years of coverage. Nice!

Servicing is due every 12 months or 15,000km, with the first seven years covered by a capped-price-service cost / maintenance cost plan. The costs are: service one - $289; two - $466; three - $360; four - $559; five - $325; six - $599; seven - $345. That makes a total cost of $2943, which is competitive for its class. Keep your owners manual or logbook up to date, and your resale value should hold up better.

If you have concerns about common problems, issues, reliability ratings and durability, you should check out our Kia Optima problems page.

The C 43 is covered by Mercedes’ five-year, unlimited kilometre warranty, which has become the new standard for the luxury car market.

Service intervals for the car are at 12 months/25,000km, which is on par with industry standard.

Mercedes-Benz Australia will offer a service plan for the C 43, prices were yet to be confirmed at the time of publication but the company has indicated it will be similar to the C300. 

That means $550 for year one, $900 for year two, the third service costs $1000 and the fourth year service costs $2450 - for a total of $4900 for the first four years of ownership.