The model reportedly has 394 bhp from a 2.5-litre turbocharged five-cylinder.
Audi's engineers only camouflage the parts on this vehicle that separate it from the standard A3. There's an aggressive front fascia with large inlets in the corners and small slits around the grille. The wings/fenders are wider, and you can get the best view of how much broader they are by looking at the vehicle from the rear.
Gallery: Audi RS3 hatchback spy shots
The vehicle also wears more prominent side sills. It rides on large-diameter wheels with seven sets of double spokes. There are big, cross-drilled brake discs.
At the rear, the wheel arches are also wider than on the standard A3. A larger spoiler is on the roof. A revised bumper has cutouts for two oval-shaped exhaust outlets.
Under the bonnet, the RS3 reportedly uses the upgraded version of Audi's 2.5-litre five-cylinder turbocharged engine. Expect it to have the same tune as the RS Q3 that produces 394 bhp (294 kilowatts) and 354 pound-feet (480 Newton-metres) of torque. These numbers put the output right between the variants of the Mercedes-AMG CLA 45 that has 382 bhp (285 kW) and 354 lb-ft (480 Nm) in the standard guise or 416 bhp (310 kW) and 369 lb-ft (500 Nm) for the S trim.
There's the possibility of an RS3 Performance with more power, according to a rumour from Germany's Auto Motor und Sport. It would reportedly make as much as 444 bhp (331 kW) to top the CLA 45 S.
Before the RS3 arrives, look for Audi to introduce the S3. It has a turbocharged 2.0-litre four-cylinder producing 306 bhp (228 kW) and 295 lb-ft (400 Nm).