What's all this about?

AMG, the performance arm of Mercedes, has been around since 1967 and to celebrate its 50th birthday, it's adding a new model to the GT family of sports cars, as well as making sundry other changes to the GT and GT S variants in the process.

So which car is the newcomer?

It's the GT C Coupe, which sits alongside the existing GT C Roadster. Like that car and the ultimate GT R model - which is the most track-focused of them all - the new GT C is wider by 57mm at the rear than its GT and GT S stablemates, making it easily identifiable. And, to further aid identification, the first GT C Coupes will be sold in Edition 50 guise, which means they come in either designo Graphite Grey Magno or designo Cashmere White Magno, with black chrome highlights on the side sills, the front splitter, the air inlet trim strips in the front grille, the front wing air outlets' fins, the rear diffuser's moulding and the exhaust finishers. The forged alloys are also shaded to match the exterior styling.

How about within the Edition 50?

Lots of black and silver. The Style Exclusive Nappa leather seats are black with grey diamond-pattern contrast topstitching, the AMG Performance steering wheel in Dinamica microfibre has a 12 o'clock mark finished in silver pearl (and Edition lettering on its bezel), and the AMG Interior Night package finishes the steering wheel spokes, shift paddles and door sill panels in black, while there's more black chrome trim elsewhere. Silver seatbelts and 'GT Edition 50' logos embossed on the head restraints complete the GT C Edition 50's cabin.

So what have we got under the GT C's bonnet?

The familiar 4.0-litre V8 biturbo, in this instance making 557hp and 680Nm. That gives it a 0-62mph time of 3.7 seconds, a top speed of 196mph, economy of 24.8mpg and CO₂ emissions pegged at 259g/km, all these figures being identical to the Roadster's stats. Mechanically, it benefits from AMG Ride Control sports suspension with adaptive adjustable damping, the bigger 390mm front discs of the GT S and GT R models (standard GTs have 360mm front stoppers, while all cars in the line-up have 360mm rear discs), standard-fit rear-axle steering (only shared with the GT R and its GT C Roadster twin) and an electronically controlled limited-slip differential (standard from the GT S upwards).

Hang on - how many AMG GTs are there now?

Six in total: four Coupes and two Roadsters. This is perhaps an ideal juncture at which to tell you about the changes to the existing GT and GT S models. So, the entry-level cars have been tweaked by 14hp and 30Nm to have peak outputs of 476hp and 630Nm; you can have the GT as either a Coupe or a Roadster, with both capable of 0-62mph in 4.0 seconds and top speeds of 188mph (for the open-top) or 189mph accordingly. Similarly, the Coupe-only GT S has benefitted from an additional 12hp and 20Nm, leading to data of 522hp and 670Nm, with a 3.8-second 0-62mph time and a 193mph top speed. Then we have the GT Cs and at the top, the 198mph GT R, capable of 0-62mph in 3.6 seconds.

What else has changed on the GT and GT S versions?

All cars in the GT family now have a Panamericana grille with larger outer air intakes sitting in the front bumpers, as well as the Airpanel active air management system (louvres in the lower front apron that automatically open and close according to whether the GT needs more cooling air or better aerodynamic properties) that was first used on the GT R now becoming standard equipment range-wide. That necessitates a move of the engine oil cooler from the front of the engine bay to a position in the wheel arch as a result. New options include the AMG Exterior Chrome package, the AMG Exterior Carbon Fibre package, the AMG Dynamic Plus package on the GT twins, new light-alloy wheel designs across the line-up and the possibility of having Style Exclusive Nappa leather trim in diamond-patterned Macchiato Beige in the GT and GT S cars. You can even specify the AMG Performance seats with climate control functions and a track-data app called AMG Track Pace is now available.

Have you got any prices or precise delivery times for the GT C?

Not as yet, with UK pricing and specification to be confirmed early in 2017, ahead of first deliveries of the GT C Coupe commencing during the summer.