The new power plant features an aluminium block and special intake and exhaust systems, which lift power and torque to 173kW and 340Nm respectively.
Alfa’s TCT six-speed twin-clutch automatic transmission has also been borrowed from the 4C, with no manual transmission on offer.
All this makes the new Giulietta QV somewhat quicker, with a new 0-100km/h time of 6.6 seconds - a 0.2 second improvement over the outgoing model - and running on to a top-speed in excess of 240km/h.
Other changes include larger exhaust tail pipes and a new paint finish to the front grille, door handles and fog light surrounds, along with new 17- and 18-inch wheel designs.
Inside, the QV gets a new instrument panel, a leather gear-shift boot and park-brake lever with white and green stitching, leather and Alcantara trimmed sports seats and a new steering wheel with white stitching.
The MiTo QV also gets a new 4C-inspired flavour, although no mechanical changes have been made.
A new Magnesio Grey matte silver paint finish and a revised rear spoiler feature externally, while the 1.4 litre turbocharged petrol engine remains from the previous model.
To celebrate the 60th anniversary of the Giulietta badge, Alfa Romeo plans a special ‘Launch Edition’ of the new QV, limited to just 500 units.
The special edition will feature a carbon-fibre spoiler and side-skirts along with an 18-inch five-spoke wheel design, wrapped in an Alfa Red, Magnesio Silver or Competizione Red paint finish.
The updated QV models are expected to hit Australia later this year, likely around September.