Track drive: AMG's brutal new GT R and GT C

Mercedes-AMG has added two new high-performance variants to its range of GT two-seater sports cars in South Africa, as AMG celebrates its 50th birthday this year.

The new GT C Roadster becomes the new flagship of the soft-top line up while the GT R, available as a hard-top coupé derivative only, is the raciest and most track-focused car offered by Mercedes-AMG.

There's also a new roadster version of the entry-level GT with outputs of 350kW and 630Nm.

Mercedes-AMG GT R

It’s nicknamed the ‘Beast of the Green Hell’ after the legendary northern loop of the Nurburgring where it spent much of its development time, and is available in an appropriate colour exclusive to this car: AMG green hell magno. If that’s too ‘foresty’ for your taste it’s available in red too.

Designed with racetrack use firmly in mind, the GT R gets a dose of extra muscle along with the ability to lay it all down with suspension, steering, braking and aerodynamic upgrades. Pumped-out front and rear fenders and a big rear wing give this R version a none-too-subtle presence. So too the Panamericana grille with 15 chrome-plated vertical bars as used in the Mercedes-AMG customer racing cars.

The 4-litre biturbo V8 gets added boost pressure to hike outputs to 430kW and 700Nm, giving the front-engined, rear-wheel drive GT R the ability to scorch to 100km/h in just 3.6 seconds, and onto a 318km/h top speed.

An active spoiler in the front underbody deploys at 80km/h to increase front downforce. This improves steering precision in high-speed cornering, which is further enhanced by active rear-wheel steering. Up to 100 km/h the rear wheels are turned in the opposite direction to the fronts, making for a smaller turning circle and more agility. Above 100km/h the rear wheels are turned in the same direction as the fronts to optimise high-speed handling stability.

An electronically-controlled limited slip differential at the rear axle maximises on-the-limit cornering grip, and the motorsport-derived traction control allows drivers to pre‑select the slip on the rear wheels in nine levels, depending on their skill and bravery.

The motorsport-derived coil-over suspension was designed specifically for the AMG GT R, and allows drivers to select their personal set-up and adjust the spring pre-load manually. AMG Ride Control adaptive damping automatically stiffens or softens the damping to suit driving conditions.

The carbon-fibre torque tube linking the front-mounted engine with the rear-mounted seven-speed dual clutch auto gearbox is about 40 percent lighter than the aluminium tube in the standard AMG GT. Further weight savings come from the standard-fit forged wheels (fitted with grippy semi-slick tyres), the titanium rear silencer, fewer soundproofing materials, and lightweight manually-adjustable AMG sports bucket seats.

All this tech adds up to a car that felt in its element when I drove it around the Kyalami racetrack, where the media launch was held this week. Having first driven the lesser AMG GT versions - and as proficient as they were - the GT R really came alive as a car that was purpose-made for scorching lap times with its crisper steering and generally sportier demeanour. For a front-engined car with a long nose, it displayed impressive flickability.

Great sound too, and the AMG engineers deserve a pat on the back for liberating such a hearty war cry from a turbo engine.

Mercedes-AMG GT C Roadster

This is the flagship in the GT soft-top line up, and wields a 410kW/610Nm version of the biturbo 4-litre V8 which is good for 0-100 in 3.7 secs and a 316km/h top speed - just a snip slower than the GT R coupe.

Like the abovementioned GT R it has wider rear shoulders than the standard GT and GT S models and the vertical-slatted Panamericana grille, along with much of the R’s racetrack-attacking tech including rear wheel steering, electric diff, and AMG Ride Control sports suspension.

It’s a more luxury-oriented model but still very accomplished around a racetrack, and drivers can adjust the car’s personality with four modes for the seven-speed dual-clutch transmission: Comfort, Sport, Sport Plus, and Race.

It too has a sound to make you want to play head-banging air guitar, and the AMG performance exhaust has variably adjustable flaps that modulate between Guns ‘n Roses and Metallica.

The electronically-controlled soft top folds up or down in a very brisk 11 seconds, at driving speeds up to 50km/h.

It’s also available in a very limited-availability AMG GT C Roadster Edition 50 with an extended range of equipment and special design features, but hurry: at the time of writing only three were left in South Africa.