Clothed in a body that uses extensive amounts of aluminium, the new Audi is claimed to possess a kerb weight that undercuts the second-generation model by an impressive 70kg, at 1445kg, providing it with a power-to-weight ratio of 204bhp per tonne.
Audi quotes a 0-62mph time of just 5.0sec with the optional S-tronic gearbox, which includes a launch control system to limit slip under hard acceleration. With the standard six-speed manual, it requires 5.5sec.
These are improvements of 0.6sec and 0.3sec over the first-generation S3 Sportback introduced back in 2008. Top speed in each case is an electronically limited 155mph, or the same as before.
The added performance is achieved with a reduction in fuel consumption; the new S3 returns an official 41mpg on the European test cycle in six-speed S-tronic guise. In six-speed manual form it is rated at 40.4mpg.
The new S3 Sportback is the latest model to use the Volkswagen Group's new modular transverse MQB platform. Among its developments is a new front end architecture, with the front axle moved 52mm further forward compared with the previous model and the engine tilted back by 12deg towards the bulkhead for improved weight distribution.
Up front is a new MacPherson strut suspension. The rear receives a revised version of its predecessor's four-link suspension. The nominal ride height is reduced by 25mm over the A3 Sportback, while the standard wheels are 18-inch diameter and come shod with 225/40 profile tyres.
Standard equipment includes Audi Drive Select. It enables the driver to alter the characteristics of the throttle, shift points of the optional seven-speed dual-clutch gearbox and the steering ratio. Heading the options is magnetic ride control, which uses an electromagnetic system to providing constantly variable damper rates.
The upgraded performance also sees the fitment of larger brakes, with 340mm discs sited up front. The traditional cable-operated handbrake has been replaced by an electro-mechanical device operated by a button on the centre console, in line with lesser A3 Sportback models.
As with the previous S3 Sportback, the new model receives a rather cautious appearance that eschews some of the more flamboyant performance car touches of rival hot hatchbacks. Many of the visual changes have already been previewed on the S-line styling package available for the recently introduced second-generation A3 Sportback.
Among them is a beefed-up grille with an aluminium-look finish to the frame and horizontal elements, larger front air ducts with honeycomb-shaped inserts within a reshaped front bumper, aluminium look exterior mirror housings, widened sills, roof rails, a prominent spoiler atop the tailgate, a deeper rear bumper with a prominent diffuser element and a quartet of chromed oval tail pipes. Discreet 'S3' badges also adorn the grille and tailgate.
The new Audi S3 Sportback is due to go on sale in September. UK prices are yet to be confirmed but expect the new S3 to cost around £34,200.