Powering the S3 is a 2.0-litre turbocharged petrol engine that produces 305bhp and 295lb ft. It features both direct and indirect injection systems, aluminium pistons, high-strength connecting rods and twin balancer shafts.
Drive is distributed among all four wheels via a six-speed dual-clutch S tronic gearbox and Audi's quattro system. Launch control and paddle shifters, for quick manual changes, are standard.
Power is sent primarily to the car's front wheels, with an electronically controlled hydraulic clutch shifting torque to the rear axle if it senses a drop in traction at the front.
Other upgrades include the standard fitment of Audi's Drive Select system and adaptive magnetic dampers, 19-inch alloys, large 340mm front disc brakes, S sport suspension – entailing a 25mm drop in ride height – and a progressive steering system with modified gearing.
Further revisions include the introduction of a new on-the-limit capability for the Audi's electronic stability control system, which permits it to apply gentle braking to the inside front wheels. This reputedly improves cornering responses at speed.
Much like the S3 saloon, the S3 cabriolet receives a range of cosmetic tweaks – including aluminium-finish door mirrors, redesigned bumpers and Xenon headlights with LED daytime running lights.
Interior changes are pleasingly restrained, comprising a flat-bottomed three-spoke wheel, grey dials with white needles and heated, S embossed front seats. It's also pleasing to see a boost gauge integrated into the instrument cluster, although it does admittedly take the place of the temperature gauge.
Standard equipment isn't exactly dazzling, with the additional premium for the S3 instead primarily going towards performance upgrades, but on the list of standard equipment is - 19in alloys, Audi's adaptive sports suspension, progressive steering system and an aggressive bodykit on the outside, while inside there is Nappa leather upholsterty, heated front seats and Audi's sound system.
That is on top of the vast amount of standard equipment bestowed on the S-Line trimmed A3 Cabriolets, including luxuries such as dual-zone climate control, LED headlights and interior lighting, rear parking sensors, an acoustic hood and cruise control, alongside Audi's 7.0in retractable infotainment system complete with DAB radio, USB and Bluetooth connectivity and sat nav.
Out on the road it's surprising how relaxed the new S3 feels with the Drive Select system in Comfort mode. The throttle response is gentle, the six-speed transmission shifts quickly and smoothly and the exhaust note is restrained at small throttle openings. The immediate impression is of a refined, competent product.
It quickly becomes apparent, however, that the S3's steering is lifeless. When turning into a corner it feels overly light and lacking in any meaningful feedback – but it is at least accurate and its responses well judged. This makes it simple to adjust and maintain your desired line.
The suspension also has its flaws. On smooth surfaces the Audi rides in a comfortable fashion but run into a pothole, a crack in the road or a broken surface, and you'll know about it.
On rougher country roads the inability of the S3's suspension to absorb smaller defects becomes increasingly apparent, with it sending persistent jitters through the cabin and controls.
Fortunately, on the flip side, the S3 does compensate somewhat with impressive cornering capabilities. There's a vast amount of grip on offer and even sharp corners, at speed, are dispatched with minimal fuss and body roll.
Like many high-performance Audis its natural bias is towards understeer but, thanks to the advanced stability control system and four-wheel drive, it's easy to further adjust your cornering attitude by modulating the power.
Switch the Drive Select into Dynamic mode and, besides sharpened responses from the engine, transmission and suspension, the steering weights up in an effort to impart more accuracy and engagement.
While the additional heft does make the driving experience a little more physical, it can be tiring and frequently feels excessive. Fortunately the Audi's Auto mode strikes a comparatively happy balance between the two, selectively refining the car's responses based on the road speed and control inputs.
Also available is an Economy mode – which has a hilariously soft throttle response but a manner that's ideal for around-town cruising – or an Individual setup where the car's responses can be tailored through a range of options.
There's no questioning the S3's straight-line performance but it doesn't deliver its power in the overly aggressive fashion that you might expect given the quoted figures. The turbocharged engine delivers its output in a very linear fashion; there's no sledgehammer blow or drama when you stand on the throttle from low speeds.
No doubt this is in part due to the S3 cabriolet clocking the scales at a not-insignificant 1620kg. What there is, however, is a remarkably deceptive ability to build speed, and continue to build speed, as the engine moves through rev range and the S tronic's ratios.
The 305bhp and 295lb ft is deployed with great ease and precision thanks to the combination of the dual-clutch transmission and four-wheel-drive system. Traction is excellent and rapid standing starts are easily achieved and repeated.
The Audi's engine might not be the most aurally evocative powerplant around, lacking the characteristic five-cylinder warble or V8 bellow of its bigger brothers, but there's enough going on to keep you interested – such as a pronounced turbocharger spooling noise, an audible dump valve and artificially induced pops and bangs during upshifts.
So it's with the deftness of the powertrain that the S3 recovers some of its driver appeal. There's a lot of enjoyment to be had winding the smooth engine out on a flowing country road, making use of the accurate steering and high degree of lateral grip to carry as much speed through corners as possible.
Braking power is more than adequate too, with a good pedal feel. This contributes to the Audi's safe, controlled and surefooted – although not hugely exciting – character.
Inside you'll find the now-familiar and comfortable cabin layout from the A3. The fit and finish is of a high standard and there's plenty of room in the front. Rear occupants don't get a vast amount of space but those up to six feet tall should be able to endure relatively long trips without too much grief, roof up or down.
With the soft-top up, refinement is good but there is considerable tyre roar on some surfaces. Drop the roof and, while not intolerable, there is a notable amount of wind intrusion into the cabin – but not so much as to leave you feeling continually blustered, or forcing you to raise your voice to engage in conversation.
A 285-litre boot and rear seats that can be lowered add a further degree of practicality to the S3, although with the roof down the available boot space is substantially compromised. There's no provision for a spare wheel either, only an oft-useless repair kit.
Despite the performance on offer the S3 is claimed to average 39.8mpg and emits 165g/km of CO2. It's not unreasonable to expect an S3 to return around 30mpg in real-world driving conditions.
Historically Audi's S models have proven potent, if not particularly rewarding to drive. Thus they are occasionally difficult to recommend, especially when pitched against typically more involving alternatives from the likes of BMW.
The S3 cabriolet is a niche model though; ultimately there's little else like it. Currently the only real contender for its high-output, four-seat, roof-down, small-footprint crown is the much loved BMW M240i, which uses the same six-cylinder 3.0-litre petrol unit found in the 40i range.
Consequently, despite its problems but given its breadth of talents otherwise, if you are tempted by a fast compact cabriolet then there is a lot of merit to picking an Audi S3 cabriolet – especially if you want something with the perceived additional safety, and all-seasons traction, of a four-wheel drive system.
Those who want a car that's more engaging on the handling front, may be best served trying the M240i Convertible.