Mercedes reveals 680PS 63 and 421PS 43 GLC Coupes

Using the same controversial powertrain as the new C63 (which is set to return to V8 power), the GLC 63 Coupe's performance is not in doubt; it gets from 0-62mph in just 3.5 seconds – nearly a second quicker than a Porsche 911 – and is limited to a top speed of 170mph. Not bad for a car that can carry five people and their luggage over tricky terrain.

As you'd expect, most of the 63's power comes from a 476PS (350kW) turbocharged four-cylinder petrol engine, which it shares with the 43. Designed and built by AMG in Affalterbach, the engine has an electrically powered turbocharger for quicker responses – the electric motor builds boost before the engine's exhaust gases can take over.

A 204PS (150kW) electric motor backs up the engine, injecting the rest of the power to the rear axle for a mountain-like 1,020Nm (752lb-ft) combined peak torque figure. 

A 6.1kWh battery gives the 63 a pure-electric range of more than seven miles and can be charged at speeds of up to 3.7kW. It also means the 63 is good for fuel economy of just over 30mpg – good for an outrageously quick (and really rather hefty) SUV.

The electric motor's ability to squirt instant torque to whichever of the car’s corners needs it means the GLC 63 can power out of slides without having to call on the help of its stability control system. The downside of the new tech is that the GLC 63 weighs a lardy 2,310kg, a substantial 300kg more than the old V8 model.

Without the full hybrid tech of its big brother, the GLC 43 4Matic tips the scales at a waif-like 1,995kg. The 43's combination of a 2.0-litre four-cylinder petrol engine with a 14PS (10kW) electric produces 421PS (310kW) 500Nm (369lb-ft) for 0-62mph in a still-nifty 4.5 seconds, while top speed is limited to 155mph.

It uses the same nine-speed auto as the 63 but sends power to the road via a purely mechanical four-wheel drive system that splits power 31:69 front to rear. Its mild hybrid system means it manages fuel economy of no better than 24mpg. 

While both versions of the GLC Coupe come with AMG Ride Control Suspension with adjustable dampers, variable-rate steering and rear-wheel steer, you can option the 63 with Active Roll Stabilisation, which uses electromechanical actuators to eliminate corner roll.

The 63 also gets beefed-up brakes, so while the 43 relies on four-pot callipers at the front and single-pot callipers at the back, the range-topper has six-pot front brakes. Break wear is also said to be reduced in the 63 by the regenerative braking effect of its hybrid system – something you'll appreciate if you've ever had to swallow the sizable bill for a set of AMG discs and pads.

From launch, the GLC63 will be available in everything-bar-the-kitchen-sink Edition 1 specification. That buys you 21-inch wheels, glossy black exterior trims and a black-and-yellow interior with 'Edition 1' logos on the front seat headrests. Included in the deal is a breathable car cover.