New Mercedes-AMG GLC 63 S E Performance 2023 review

Verdict

The new Mercedes-AMG GLC 63 S is all change, trading the last car’s burbling V8 for a more future-focused plug-in hybrid powertrain derived from its Formula One know-how. But with it has come a confounding level of technical complexity that feels neither finessed or particularly engaging, with negligible benefits in day-to-day driving.

The new Mercedes-AMG GLC 63 S shares a vast majority of its new technical hardware with the C 63 saloon launched last year, controversially dropping the previous V8 engine for a cutting edge plug-in hybrid powertrain packed full of future-proofed technology. 

The addition of ‘E Performance’ might create a clumsy name, but it also produces a substantial 671hp maximum output. It does this by pairing a turbocharged four-cylinder petrol engine – one shared with the A 45 S hot hatchback – to a plug-in hybrid module. The battery pack and electric motor are located on the rear axle, the latter producing 201bhp in boost mode for a maximum of 10 seconds, or 107bhp at a constant level.

In typical AMG style, there’s a bewildering array of tech to forge through, with a total of eight driving modes augmenting how the combustion engine and the electric motor interact in any given situation. But it’s worth mentioning that despite being able to plug-in, its tiny eight-mile EV range isn’t designed to enhance efficiency or lower running costs. 

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Instead, the 6.1 kWh battery and associated hybrid system is all about boosting the petrol engine to reach those lofty power figures. Indeed, a quarter of its capacity is always held back in order to be able to boost, even when the battery shows as empty on the dash. 

Unfortunately, the plug-in hybrid powertrain never really feels worthy of its headline power figure. Accelerating out of a corner in a traditional V8-powered AMG was a case of progressively feeding the throttle before feeling the car move around. With the new car, it seems so complex that all you can really hope to do is put your foot down and hope for the best. 

This tech comes with other compromises, too. Its colossal curb weight of 2,235kg is just too much to overcome, despite packing plenty of chassis technology designed to try and disguise it. Standard rear axle steering helps get the nose turned in and keeps the rear tucked neatly behind, but there’s now so much momentum and inertia that any sense of engagement is lacking, at best. It makes rivals like an Alfa Romeo Stelvio Quadrifoglio or BMW X3 M Competition feel like tiny sports cars by comparison, and that’s before we even consider traditional estate rivals. 

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The coil-spring suspension is paired with adaptive dampers and an active anti-roll system in place of the previous GLC 63’s air-sprung setup and does feel better for it. In ‘Race’ it’s very firm, but well controlled, softening off in its lesser modes to suit more everyday scenarios. 

The brakes, on the other hand, still have some rough edges. Like most hybrids, they blend both regenerative and friction braking systems, but as several rivals now crack the difficult job of combining the two, AMG still has its issues. Initial pedal feel is largely dead, and modulation is particularly poor. When you do find the bite-point, you realise the brakes are also overworked by the car’s potential for great speeds and the mass they have to slow down. 

At £108,000, it’s also very expensive for a mid-size SUV. It’s a price that despite being fully kitted up here in the UK, isn’t really represented in the cabin quality or materials, either. All the tech is there, including brilliant Digital LED headlights and an intuitive infotainment system, but the material quality is lacking. This is a sentiment shared with GLCs that cost barely half what the 63 does, which only makes the shortfall of this AMG flagship all the more glaring. 

Yet its biggest issue remains its puzzling lack of desirability. To the SUV crowd that want the latest, extraverted high performance family car, the GLC’s lack of a V8 will be a problem. If you’re more concerned with an engaging driving experience, it has issues there too.