In this head-to-head review, David Taylor and Ash Oldfield pit 2 of Affalterbach’s most potent V8 machines against each other: the elegant Mercedes-AMG SL63 convertible, and the ferocious, plug-in hybrid-powered Mercedes-AMG GT63 S coupe.
In the exclusive world of Teutonic ultra-high-performance road cars, Mercedes-AMG often finds itself competing against its own creations, which is exactly the case with the SL63 and GT63 S coupe!
The difference in the 2 models’ multi-million-rand price tags (R3 983 284 and R4 386 749, before options, in November 2025) isn’t huge (in relative terms), leading to 1 crucial question: when spending this kind of money, do you opt for the sun-seeking open-top grand tourer, or the hybridised rocket ship?
See also: Mercedes-AMG E53, CLE53, SL63 & GT63 S – Launch Review
The Return of V8 Thunder: Mercedes-AMG SL63
Many believe a Mercedes-AMG SL must have a V8 engine – and after the (now locally discontinued) 2.0-litre 4-cylinder powered SL43 initially underwhelmed – ‘Benz has given the purists what they want.
The Mercedes-AMG SL63 is powered by the Three-pointed Star’s 4.0-litre twin-turbo V8 (M177), which produces a muscular 430 kW/800 Nm that is channeled through an all-wheel-drive system.
David spent time behind the wheel of the SL63, focusing on how Mercedes-AMG has balanced the grand tourer credentials of the brand’s roadster (now in its 7th generation) with modern sportscar dynamics.
While the current iteration of the Mercedes-AMG SL is designed for gentle, open-road cruising, its performance figures hint at a different character. The roadster features a sporty suspension tune and rear-wheel steering that facilitates impressive grip and connection to the road when tackling corners.
David notes that the SL63‘s driving modes offer a genuine split personality. While Comfort ensures a genuinely luxurious and relaxed convertible experience – complete with Mercedes’ famed Air Scarf – switching to Sport+ or Race mode sharpens the car’s responsiveness and stiffens the damping.
This provides a highly satisfying level of driver engagement for performance driving, although the SL63‘s ride quality (especially in sportier modes) is compromised on uneven and pockmarked road surfaces.
See also: Mercedes-Benz CLE cabriolet (2025) Review
The Hybrid Beast: Mercedes-AMG GT63 S coupe
Lining up as the SL63’s sibling rival is the Mercedes-AMG GT63 S coupe. In this video review, David is joined by our resident “tame racing driver”, Ash Oldfield, who pilots the plug-in hybrid GT63 S coupe.
The GT63 S coupe represents a new breed of hyper-performance. It combines AMG’s hand-built 4.0-litre twin-turbo V8 with a 150 kW permanently excited synchronous electric motor (on the rear axle).
This plug-in hybrid setup delivers staggering combined outputs of 600 kW and a massive 1 420 Nm of torque, making it the most powerful production car Mercedes-AMG has ever created.
Ash describes the GT63 S coupe as potentially the most dynamic Mercedes-AMG model he has ever driven, and one that attempts to completely rewrite the rules of physics for a car of its size and power.
The ‘Benz hides its kerb weight (just under 2.2 tonnes) remarkably well and provides immense stability, partly due to the weight distribution over the front axle and its complex drivetrain technologies.
The discussion also touches on the long list of options fitted to the GT63 S coupe, among them is carbon ceramic braking system – a feature Ash highlights as great for track days (due to the brakes’ resistance to fade), but which can feel less responsive during everyday commuting than traditional steel discs.
See also: 2020 Mercedes-AMG GT 63 S Review – Is this really a supercar?
The hardtop smashes the Launch Control challenge
To truly settle the debate on raw, straight-line pace, the team subjects both cars to performance testing.
The SL63 has a claimed 0–100 kph time of 3.6 seconds, but when David tested our test unit he managed to shave a fraction off that time, confirming the roadster’s ability to pull away with incredible efficiency.
The GT63 S coupe, being the 2-door flagship Mercedes-AMG, makes an even bolder claim: 0–100 kph in a mind-bending 2.8 seconds. After a quick analysis of the testing conditions and some adjustments, Ash and David (acting as the timekeeper) manage to achieve sub-3-second acceleration runs.
A fastest recorded time of 2.99 seconds confirms the GT63 S coupe as one of the fastest production cars ever tested against the clock by Cars.co.za, showcasing its brutal, electrically-assisted thrust.
See also: GLE 53 – The sweet spot in Mercedes-AMG SUV line-up?
How much does Mercedes-AMG SL63 & GT63 S coupe cost?
| Mercedes-AMG SL63 | R3 983 284 |
| Mercedes-AMG GT63 S coupe | R4 386 749 |
Prices (before options, in November 2025) include a 2-year/unlimited km warranty and a 5-year/100 000 km maintenance plan. The GT63 S coupe‘s hybrid battery has an 8-year/160 000 km warranty.
New Mercedes-AMG SL Specs & Prices in South Africa
Find a Mercedes-Benz SL listed for sale on Cars.co.za
Find a Mercedes-AMG SL listed for sale on Cars.co.za
New Mercedes-AMG GT Specs & Prices in South Africa
Find a Mercedes-AMG GT listed for sale on Cars.co.za
Summary
When the dust settles, the choice between the Mercedes-AMG SL63 and its GT63 S coupe sibling is immensely difficult. Both cars are technical masterpieces delivering next-level performance, yet they cater to fundamentally different tastes: the SL63 offers the joy of a V8-powered convertible grand tourer, but augmented with impressive athleticism, while the GT63 S coupe is the unapologetic, plug-in hybrid-boosted supercar. The small difference in price (in relative terms) further complicates the decision.
To find out which car David ultimately decides to take home – the elegant roadster or the ballistic plug-in hybrid coupe – you’ll have to watch the video!
Frequently Asked Questions (FAQ)
Q: What is the main difference between the Mercedes-AMG SL63 and GT63 S coupe?
A: The SL63 is an open-top V8-powered grand tourer offering elegant convertible motoring with impressive athleticism, while the GT63 S coupe is a hardtop plug-in hybrid “rocket ship” delivering extreme performance with combined outputs of 600 kW and 1 420 Nm.
Q: How much do the Mercedes-AMG SL63 and GT63 S coupe cost in South Africa?
A: In November 2025, the Mercedes-AMG SL63 is priced at R3 983 284 and the Mercedes-AMG GT63 S coupe at R4 386 749 (both before options), with prices including a 2-year/unlimited km warranty and a 5-year/100 000 km maintenance plan.
Q: How quick are the SL63 and GT63 S coupe from 0–100 kph?
A: The SL63 has a claimed 0–100 kph time of 3.6 seconds and achieved slightly quicker times in testing, while the GT63 S coupe – claimed at 2.8 seconds – recorded a best tested time of 2.99 seconds, confirming it as one of the fastest production cars ever tested by Cars.co.za.
