BMW 8 Series vs Porsche Panamera GTS vs Mercedes-Benz GT53 4Matic+: best value for money

The large GT car segment has long between dominated by ultra-premium products such as the Bentley Continental GT, the Ferrari GTC4 Lusso, various Aston Martin products and more recently, McLaren had a stab at it with its GT. However, there has been a movement towards more attainable GT cars with the introduction of the BMW 8 Series and Mercedes-AMG's GT 4-door models, which now provide the Porsche Panamera with more natural rivals.

With the premium GT car segment quite literally bustling with contenders across a variety of price points, it was important for us to nail down one 8 Series variant and determine which products are its most natural rivals from a price and performance perspective.

We decided on the M850i xDrive Gran Coupe as it has four-doors, much like its key rivals while also coming in close in terms of pricing versus the Mercedes-AMG GT53 4Matic+ and the Porsche Panamera GTS. Those in the market for one of these vehicles will have a tough decision to make when it comes to choosing which one belongs in their garage. Our goal today is to determine which one from this trio represents the best value for money.

Related: BMW M850i xDrive Convertible (2019) Review: Larger than life

The competitors

	BMW M850i xDrive Gran Coupe	Mercedes-AMG GT53 4Matic+ 4-door coupe	Porsche Panamera GTS
Engine size	8-cyl, 4.4-litre turbo petrol	6-cyl, 3.0-litre turbo petrol	8-cyl, 4.0-litre turbo petrol
Power/Torque	390 kW/750 Nm	336 kW/520 Nm	353 kW/620 Nm
Kerb Weight	2 070 kg	2 045 kg	2 020 kg
0-100km/h	3.9 sec	4.5 sec	3.9 sec
Airbag count	6	7	8
Load Volume	440-litres	456-litres	495-litres
Price	R2 172 200	R2 280 680	R2 389 000
Claimed consumption	10.7 L/100 km	9.4 L/100 km	10.9 L/100 km
Maintenance plan	5 yr/100 000 km	5 yr/ 100 000km	3 yr/100 000 km
Tank capacity	68-litres	66-litres	90-litres
Top speed	250 km/h	285 km/h	300 km/h

Comparing the trio

Practicality

These GT cars are likely to be owned by keen drivers who value cross country comfort, luggage capacity and performance.  In terms of dimensions, all three products are quite similar, however, the M850i is the longest and has the longest wheelbase while the Mercedes-AMG is the tallest and the widest while the Panamera is incredibly similar to the GT53 in terms of its length and wheelbase.

When it comes to occupant space, the BMW is the only product to offer seating for five occupants as standard while the Mercedes-AMG has four seats as standard with an optional fifth seat. The Panamera has just four seats, however, the Sport Turismo version of the car has what the brand calls the ‘4+1’ seating concept. The centre seat in both the BMW and the Mercedes-AMG products are not as well suited to longer journeys as the other seats, making all the products more suitable as four-seat models across longer journeys. When comparing the boot space, we see the Porsche coming out on top, offering 55-litres more luggage space than the BMW and 39-litres more than the Mercedes-AMG.

Power and performance

The engines in the three contenders are all powerful, and all the models here have the benefit of all-wheel drive systems. However, it is the V8 in the BMW that produces the most power and torque thanks to its superior displacement while the V8 in the Panamera produces 37kW and 130Nm of torque less than in the M850i.

The Panamera is 50kg lighter and has a faster 8-speed dual-clutch gearbox versus the 8-speed torque converter in the BMW, meaning that the acceleration figures for the two vehicles are identical, on paper at least. The BMW is however electronically limited to 250km/h while the Porsche will go to reach 300km/h while the GT53 sits in the middle with a top speed of 285km/h.

The GT53 has the smallest engine in this test, an inline-six that is turbocharged and assisted by a 48-volt mild-hybrid system and a dual-clutch 9-speed automatic gearbox. It produces impressive figures, but none that will challenge the 8-cylinder competitors in this test.

While fuel consumption is of less importance in sporty GT vehicles than it is in many other vehicles, it is still worthy of consideration, especially when combined with the size of each vehicle’s fuel tank as products such as these will be used to cover long distances where lengthy driving range and fewer fuel stops are better suited to the character of the vehicle. When comparing the fuel tank size versus the claimed consumption, it is the Panamera that comes out on top, offering 826km of range on a single tank of fuel, followed by the GT53 at 702km and the M850i at 636km.

Specification

From a specification perspective, all three models come with large alloy wheels, the BMW and Porsche 20-inch items and the Mercedes-AMG 19-inch wheels. As is to be expected, all three come with climate control, an electrically adjustable multifunction steering wheel, infotainment systems with smartphone and voice control functionality, a reverse camera and cruise control (adaptive in the BMW). Of the trio, it is only the Panamera that comes with air suspension as standard while the M850i and GT53 make do with regular coil-sprung systems.

The trio also comes standard with other rear ISOFIX child seat anchor points, front and rear electric windows and side mirrors, electrically adjustable front seats, auto LED headlights, front and rear Park Distance Control and electric tailgates. The BMW is the only model to get keyless entry and start while the GT53 and Panamera get keyless start. The Panamera and M850i get lane departure warning and surround-view cameras but the BMW also gets a blind spot monitor, soft-close doors and a self-parking system which also come standard in the GT53. The BMW also comes as standard with leather seats while both the Porsche and the Mercedes-AMG come with suede-cloth and artificial leather as standard.

Safety

The 8 Series has yet to be tested by the likes of EuroNCAP, however, the product is based upon the brand’s CLAR modular platform that it shares with the 5 Series, 7 Series and a variety of other BMW products. The 8 also shares its safety systems with other BMWs that have received the maximum 5-Star safety ratings, making it reasonable to assume that it is a safe vehicle.

The Panamera range is also yet to be crash-tested, however, much like the BWM, it comes from a brand renowned for safety. It also offers the most airbags in the comparison and a variety of safety items that are sure to make it at least as safe as the likes of the Macan, or at least close to as safe as the all-electric Taycan, which both scored the maximum 5-Stars.

As with the other niche contenders in the comparison, the GT 4-door is also yet to be crash-tested, however, like the BMW, it shares a platform and safety features with other products from within its own stable, namely the E-Class and S-Class, which both achieved 5-Star safety ratings.

Warranty & maintenance plan

All three of these contenders are sold with maintenance plans that span 100 000km, however, the Porsche has the shortest standard duration at 3-years, which can be extended to 5-years, while both the Mercedes-AMG and BMW feature  5-year maintenance plans.

Verdict

The trio of products that we have assembled for this comparison are exceptionally competitive. While the Mercedes-AMG is just that, a pukka AMG developed by the masters in Affalterbach, it is simply too expensive and lacking in the performance arena to compete with both the Porsche and BMW when determining the best bang for your buck.

That leaves the Panamera and the M850i, two potent V8-powered GT bruisers from two fantastic motor manufacturers. Looking at the statistics, the two products trade blows in performance and specification throughout the entire comparison, however, the R216 800 premium that the Porsche commands versus the BMW mean that the 8 Series claims victory in this test.

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