The Mazda3 is the engine that drives Mazda’s Zoom-Zoom image, with 2 million copies sold worldwide since its introduction five years ago: That’s one out of every three Mazdas sold. So, what path does a carmaker take when it comes time for an updated edition of its top-selling vehicle? Mazda chose a safe route for the 3 with an evolutionary exterior and interior restyle along with skillful mechanical tweaks. The result is a compact car that has a more appealing appearance and more Zoom-Zoom driving dynamics than the outgoing model.

The November Los Angeles Auto Show was chosen for the 2010 Mazda3 sedan’s introduction, while the 5-door made its North American debut today in Detroit. The primary difference is a hatch versus a trunk body style.

A distinctive new frontal treatment, formed by a larger five-point grille and lower corner intakes, is representative of future Mazda styling. The car takes on an aggressive stance that’s low to the ground with sweeping aerodynamic curves emphasized by bulging front wheel arches.

It takes only a quick glance to note that interior quality has been refined with the use of soft-touch materials and attention to details. Reflecting the new Mazda6, the cockpit is driver-oriented and features barrel instrument gauges. A curved indent on the top of the dash slanted towards the driver houses the trip computer and a navigation screen.

Like all small front-drive cars, the 3 is best-suited for four people, not the 5-passenger hauler billed by manufactures. As for hauling cargo, there’s nearly 44 cubic feet of cargo volume with the split-folding rear seats down.

Unlike the sedan, the hatchback model will not offer a 148 horsepower 2.0-liter 4-cylinder engine. The only powerplant will be the 2.5-liter four borrowed from the Mazda6. Output is 167 horsepower and 168 lb-ft of torque.

A 6-speed manual or 5-speed automatic with manual shift mode are the transmission choices. Highway fuel economy is rated at 29 mpg with either transmission.

Body rigidity has been increased and engineers improved suspension damping to improve roll control and maintain a flatter ride.

In addition to performance, the Mazda3 5-door offers a laundry list of bells and whistles not found in its class: steering-linked bi-xenon headlights, Bluetooth hands-free phone and audio capability and dual-zone climate control.

Die-hard fans, of course, are eagerly awaiting the next Mazdaspeed3, which is always a 5-door. Maybe this spring’s New York Auto Show?