The seventh-generation compact has been renewed all round, with improvements to the chassis and engines along with enhanced creature comforts.
The 3 Series defines the sector for compact sports sedans, and BMW is keen to keep ahead of its closest rivals Mercedes-Benz and Audi.
Codenamed G20, the new car rolls into showrooms early next year after the dust wrappers came off the shape at the Paris Car Show earlier this year.
The new 3 Series is slightly longer yet 55 kilos lighter than the version it replaces, thanks to the use of aluminium bumpers, front struts, front subframe and roof. This weight saving is rare at a time when gadget-loaded new cars are getting heavier.
The 3 Series is stiffer, too, and comes with a wider track and lower centre of gravity in order to boost handling and drivability. Lighter steering makes for an agile set-up.
The engines are familiar, with a 150-horsepower diesel in the entry-level 318d. It burns just 4.1 litres of fuel per 100km. The 320d and 330d offer more oomph.
Many buyers will opt for the evergreen 320i, which uses a turbocharged two-litre, four-cylinder petrol motor with 184 horses.
The premium 330i pushes more horsepower and can be ordered with rear-wheel drive or BMW's xDrive all-wheel drive system.
The design of the new 3 Series is evolutionary and brings the car into line with the look of the rest of the range. At the front, the headlights slant downwards to connect with the trademark kidney grille.
The interior is all new, with a 5.7-inch digital gauge cluster and re-jigged 10.25 infotainment screen in the centre of the dashboard. The latest iDrive system is on board, along with a suite of driver assistance systems.
The rubber-burning fraternity can look forward to a powerful M340i sports version. A plug-in hybrid, which can manage 50km on electric power alone, is in the pipeline. Estate versions and a GT are also set for release.
The M340i and its interior (below).
