Mazda's best-selling vehicle worldwide, the Mazda3, gets a major makeover for 2010--a new engine and transmissions, reshaped sheetmetal and a revised interior, and a few surprises.

Mazda revealed the second-generation subcompact sedan at the Los Angeles auto show. The five-door hatchback version should make its debut soon--maybe as early as this December's Bologna, Italy, show. The sedan and hatchback go on sale in the United States in the first quarter of next year.

So what's in store for Mazda's award-winning small car that has sold some 1.8 million copies worldwide in five years on the market?

"On the heels of the original Mazda3's success, we aimed to again exceed the expectations of customers all over the world by a wide margin," Program Manager Yoshiyuki Maeda said. "This meant providing drivers with a sense of exhilaration whether they were in motion, seated in the Mazda3's cockpit, or enjoying its appearance from outside."

Enough of the zoom-zoom-speak--what Maeda really means is that he tapped Mazda's global engineering resources in Japan, Europe and the United States to produce an encore to what was already a damn fine little car.

Whether Maeda and Mazda succeeded can be measured in many ways, not the least of which is the all-new exterior and interior designs.

Rather than starting with a blank slate, chief designer Kunihiko Kurisu retained the Mazda3's strong existing cues but evolved the styling with even stronger lines. The car gets the company's global face, with a single, lower and larger five-point grille replacing the two-piece look in the current model. Borrowing from the redesigned 2009 Mazda6's coupe-like profile, the Mazda3's side view features distinctive character lines that tie together the high rear deck and the front fascia. Self-leveling bi-xenon headlamps, standard on Grand Touring models, make Mazda3 the first U.S. compact to offer the advanced lighting system. All headlights pick up repeating lines previewed on several Nagare concept cars.

The Mazda3's redesigned cabin incorporates a large gauge cluster, center stack and controls positioned close to the driver. Key ***** and switches are positioned at the same level as the steering wheel and the shifter.

Front seat cushions have been extended by nearly an inch, backrests are 1.4 inches taller, and upper side bolsters are canted inward on upper trim models. A three-position memory function is now standard on cars with power seats.

The Mazda3's already sharp interior lighting goes interactive for 2010. Upon opening the door, foot well and door handle lamps illuminate, followed by the instrument cluster, center stack, audio and climate controls. When audio or ventilation switches are touched, lighting changes to provide a visual cue acknowledging the command.

Options for 2010 include dual-zone climate control, a Bose 10-speaker premium surround sound system, connectivity for cell phones and portable media players, a dock for iPods, Sirius satellite radio, keyless entry system with push-button engine starting, rain-sensing wipers, heated side mirrors, leather upholstery and heated seats.

New under the hood is a 2.5-liter four-cylinder engine borrowed from the Mazda6. The engine produces 167 hp and 168 lb-ft of torque (up from 156 hp and 150 lb-ft from the 2.3-liter engine in the current car). The base engine remains a 2.0-liter, 148-hp, 135-lb-ft inline four.

The larger engine comes with a six-speed manual gearbox (up from five speeds), while the 2.0-liter unit is hitched to a standard five-speed manual (up from a four-speed). A five-speed automatic is optional with either engine. Fuel economy is generally on par with the current model, but highway mileage improves by 3 mpg on the 2.0-liter with the stick.

Want to stump your dealer? Ask about the catalytic converters, which use nanotechnology to reduce the use of expensive platinum and palladium in the catalysts by 70 to 90 percent. Just tell your salesperson to take it off the sticker price.

Mazda manages air flow to the radiator and intake via a guide attached to the front bumper that directs the flow through the radiator. At high speeds, a bypass flap opens to minimize drag.

Mazda engineers didn't tinker too much with the already agile and strong Mazda3 unibody chassis, but they did employ some of the structural tricks learned from the Mazda6--such as the judicious application of structural adhesives and a third steering gear mounting point--to improve the car's overall stiffness and handling.

The braking system is upgraded with a new vacuum booster that provides good, light pedal response without overboosting hard braking.

All the parts come together to make the Mazda3 better than its already good predecessor, with a direct and linear steering feel, rigid chassis and well-sorted suspension, and sufficient engine power for the car's size and weight.

Extra effort to manage the kind of thrash typical in a larger four-cylinder engine is well-managed via double crankshaft dampeners. Suspension changes minimize body roll and dive, without making the car too harsh over rough roads. Interior dimensions don't change, but there's plenty of seat support to ride for many miles in the new car.

Pricing won't be released until closer to the car's on-sale date, but Mazda officials say the car will maintain its position compared to competition such as the Honda Civic and Toyota Corolla.