What happens when fire meets ice? Conventional thinking would say that the fire will melt the ice. But if the ice is cold enough, it might just extinguish the fire.

The fire in this story is the 911 Carrera GTS, which sits between the Carrera S and Turbo models in the 911 line-up. Its athleticism is reflected in its fiery Carmine Red paintwork and aggressive-looking 20-inch wheels finished in Satin Black.

Also painted black are the 911's air intakes, engine cover and tailpipes. The GTS also has a rear end that is 44mm wider than that of the Carrera and Carrera S models. This added width not only endows it with better roadholding, it also gives the GTS more flair on the road.

But when it comes to sheer road presence, the AMG GT S - the ice in this story - overshadows the 911 GTS. Within Mercedes' model range, the AMG GT S is the successor to the gull-winged SLS AMG and the tristar brand's flagship sports car.

With its diamond-stu

dded grille, long bonnet and curvaceous rump, the AMG GT S looks cool yet dramatic. It sits really low to the ground and looks ready to race.

The Merc's cockpit is sensual and aircraft-like. Inside, you sit closer to the ground than in the Porsche and feel more ensconced at the same time, thanks to the thick centre console. The air-conditioning vents resemble jet turbines and there are lots of knobs and buttons too.

In contrast to its fiery exterior, the 911 GTS' interior is relatively muted. Although most of the cabin is covered in Alcantara and there is lots of red contrast stitching on the seats and dashboard, the overall feel is still sombre rather than exciting. However, the whole layout is more intuitive than in the AMG.

While drivers might have to spend a few minutes figuring out the switches in the AMG GT S, they will be rewarded with a more customised driving experience. The AMG Drive Unit, for instance, lets drivers choose one of four settings (Comfort, Sport, Sport Plus and Race) that simultaneously adjust the engine, transmission, traction control and damper characteristics.

Although the AMG GT S looks cool, its performance is red-hot. Motivating this sexy coupe is a twin-turbocharged four-litre V8 that pumps out 510bhp and 650Nm.

Instead of the turbos being mounted on the cylinder banks, they are actually located within the "V". This results in a more compact engine that can be installed lower too.

AMG models are known for their exceptionally loud soundtracks and the AMG GT S does not disappoint. The V8 fires up with an intimidating roar, like a beast woken from its slumber. It rumbles at low revs and growls more and more menacingly as the revs climb.

Piloting the AMG GT S is a pulse- pounding and emotionally draining experience. Controlling the 510bhp requires finesse, as the throttle is sensitive and the gearbox can be overly snappy.

Point the long bonnet down a straight road, nail the throttle halfway and you will be rocketed towards the horizon. The coupe's 0-100kmh time of 3.8 seconds could also be how quickly your driving licence is taken away by the cops.

The impressive performance of the AMG GT S makes the 911 GTS seem meek, but the Porsche must not be underestimated. Behind its rear axle sits a naturally aspirated 3.8-litre flat-six capable of 430bhp and 440Nm. Even without forced induction, it will still go from nought to 100kmh in four seconds flat.

The 911 GTS is not as loud as its rival, but its vocals are no less stirring. The mechanical voice of its flat-six and the gruff exhaust notes are titillating. The Porsche even has a more compelling overrun - the rough crackle-and-pop is truly racecar-like.

Driving the AMG GT S takes more out of the driver. Sure, it offers plenty of grip in corners, but its helm has less feel than expected. Its long bonnet and thick A-pillars are also liabilities around town. You will need to push the car's nose out into a junction before you can see cars approaching.

The 911 GTS, on the other hand, is much easier to handle. There is no long bonnet to peer over and the car's slightly higher ground clearance means you do not worry when entering multi-storey carparks.

Yet, the 911 GTS can demolish bends. Its rear-engine configuration gives its driven wheels even more grip, while the responsive and well-weighted helm helps the driver to position the car with precision. Its 7-speed dual-clutch gearbox is also smoother and quicker than the AMG's transmission.

Whatever effort you put into driving the Porsche is exactly how much performance it will deliver. The 911 GTS is hot because it makes you want to drive it hard and fast.

But it is the AMG GT S that delivers. Not only is this coupe a powerful car, it is also a treat for the senses.

• The writer is with Torque, a motoring monthly published by SPH Magazines.