BMW’s top-selling 3 Series variant in recent years, the entry-level four-cylinder 320i, has returned to the fold after a model-change hiatus.

The 320i is now armed with a more powerful and more fuel-efficient turbocharged direct-injected 2.0-litre petrol engine – a detuned version of the N20 engine from the 328i that kicked off sales of the new sixth-generation F30 3 Series earlier this year.

Alongside the 320i at the bottom of the 3 Series range is a new model, the diesel 318d, that uses a detuned version of the 2.0-litre diesel engine in the existing 320d, while also losing a few bells and whistles to create a price leader to attract fresh customers to the Bavarian brand.

With sub-$60k pricetags, these most affordable 3 Series models are expected to do much of the heavy lifting in the showroom as BMW looks to claw back Mercedes-Benz C-Class’s lead in the medium-size luxury-car class.