The Chevrolet Cobalt comes in two-door coupe and four-door sedan body styles, and in base, LS, LT, and SS trim levels.The base engine produces 155 horsepower and qualifies the Cobalt as an Ultra Low Emissions Vehicle; these models come standard with a five-speed manual transmission and a four-speed automatic is an option.The base version of the Cobalt is EPA-rated at 25/37 mpg City/Highway with the five-speed manual transmission.

The Cobalt SS is powered by a turbocharged 2.0-liter four rated at 260 horsepower and 260 pound-feet of torque.A heavy-duty five-speed manual is the only transmission available with the SS.The SS is available only as the coupe.

For 2010, Chevrolet Cobalt changes are few.The My Link package includes an AM/FM/CD/MP3/USB audio system with Bluetooth connectivity, cruise control, leather-wrapped steering wheel and shift knob, steering-wheel audio controls, OnStar Directions and Connections, and 16-inch alloy wheels.The power sunroof and performance display are standard on the SS model.

Cobalt LS ($15,670) sedan and coupe come with air conditioning, wind-up windows and manually operated mirrors.Tires are low-rolling-resistance 195/60R15s on 15-inch steel wheels.Options include an automatic transmission ($925) and anti-lock brakes ($400).

Cobalt LT ($16,470) sedan and coupe get upgraded upholstery, adjustable lumbar support for the driver, power windows and door locks, power mirrors, remote keyless entry, carpeted floor mats front and rear, a console with an adjustable armrest and two 12-volt outlets, and other amenities.Options include cruise control ($275), a Sun & Sound Package ($995) that includes a sunroof and seven-speaker Pioneer audio system, remote vehicle starter ($190) for automatic models, heated leather seats ($795), and a leather-wrapped steering wheel with audio and cruise controls and Bluetooth wireless connectivity ($245).The 2LT package ($1,370) includes anti-lock brakes, cruise control, and 205/55R16 tires on alloy wheels.The Sport Appearance Package ($995) includes a rear spoiler, larger body-color fascias and rocker moldings, 17-inch polished aluminum wheels with performance tires, chrome exhaust tip, fog lamps, white-face sport gauges, and leather-wrapped steering wheel and shifter knob.A Bright Chrome Appearance Package ($295) includes a chrome grille, bodyside moldings, door handles, exhaust tip and front and rear fascias.

Cobalt SS coupe ($24,535) is powered by a 2.0-liter turbocharged engine and comes with upgraded suspension and brakes, sport seats with suede-like inserts, additional gauges, fog lamps, and spoilers and air dams all around.A heavy-duty five-speed is the only transmission offered.Tires are 225/40R18 on 18-inch forged aluminum wheels.A configurable LCD display allows the driver to select from a variety of performance measurements, including 0-60 mph and quarter-mile acceleration, braking performance and cornering force.Options include sport pedals ($165) and a limited-slip differential ($495).

OnStar, in one form or another, is standard on all models.It's a good safety feature because operators will direct emergency crews to your exact location should your airbag go off and you fail to respond.It also includes the General Motors Advanced Automatic Crash Notification (AACN) system, making crash data available to participating 911 centers to help them dispatch the appropriate live-saving personnel and equipment.

Safety features include dual-stage front air bags, front seatbelt pre-tensioners, rear center shoulder belts, and the LATCH child seat retention system.Head-curtain side airbags are standard on all models, as is a tire pressure monitor.The SS model has StabiliTrak electronic stability control.Anti-lock brakes (ABS) are standard on the SS, included in the 2LT option, and optionally available on the LT and LS.

Body panel fits are extremely tight.So tight, in fact, that there are no rubber trim gaskets around the Cobalt's compound complex headlamps.

The coupe weighs about 50 pounds less than the sedan, a relatively insignificant amount.

The Cobalt is longer, wider and lower than most of its direct competitors.Its interior dimensions and trunk capacity are comparable for the class.

The Cobalt SS is distinguished by its front fascia with integrated air dam and projector-beam fog lights.Upper and lower grilles both sport a specific diamond-mesh texture.Rocker extensions are also unique to the SS, and a rear deck-lid spoiler is standard.The standard spoiler can be replaced with big wing.The rear is finished off with a bright-tip exhaust outlet.

The Cobalt uses different seats in the different trim levels, each with detail changes in foam, padding and trim.We found plenty of fore/aft travel and rake adjustment for a 6-foot, 4-inch driver, plus seat-height adjustment with a ratcheting handle.The LT seats were very comfortable and grabbed us in the fast corners exactly where we needed to be grabbed and held.Even better were the optional leather-trimmed seats, which come with electric heat.

Inside the SS are sport seats embroidered with the SS-logo and enhanced with suede-like UltraLux inserts.A specific gauge package includes an A-pillar-mounted turbo boost gauge.

The available Pioneer seven-speaker sound system with the Delphi AM/FM/CD delivers good sound and includes a huge subwoofer mounted on the left side trunk wall.And all Cobalts come with XM Satellite Radio.

The heating, ventilation and defroster system worked quickly and intuitively.

The Cobalt LS comes with manually operated windows that take a lot of cranking (about four and half times around) to wind the windows up.The urethane steering wheel that comes on LS and LT models feels cheap.The leather-wrapped wheel that's optional on the Cobalt LT is much nicer.

Rear-seat passengers pay a price for the coupe's sporty looks.Headroom, legroom, and hip room are reduced by 2 inches, 1.5 inches, and 3.5 inches, respectively; enough to make the difference between a comfortable place for adults and one best left to pre-adolescents.Up front, the coupe actually offers more head and legroom than the sedan, but only by fractions of an inch.Therefore, the coupe is a good choice for drivers who are usually alone or with a friend, while the sedan is the better choice for drivers who often find themselves with two or three passengers.

The trunk in the sedan is wide and deep with a low lift-over height, and almost 14 cubic feet of capacity, more than competitive in the class, though the opening to the trunk seems relatively small.The trunk lid uses outside corner hinges and two hydraulic assist struts instead of gooseneck hinges that can squash groceries when the lid is closed.The coupe has the same trunk volume but an even smaller trunk opening, making it difficult to stow a thick suitcase.A 60/40-split, fold-down rear seat with a trunk pass-through feature adds utility to both sedan and coupe.

The variable valve timing helps fatten the torque curve through a wide range of engine speeds.EPA-estimated fuel economy with the 2.2-liter engine, manual transmission, and standard low-rolling-resistance tires is 25/37 mpg City/Highway.With any of the larger tire options that slips slightly to 25/35 mpg, which is still within the ranges of the likely competitors.With the automatic transmission, the Cobalt is rated at 24/33 mpg.

The brakes seemed a little mushy on the LT and LS models we drove, which come with drums in the rear.

The Cobalt SS is powered by a 2.0-liter turbocharged and intercooled Ecotec four-cylinder that uses direct fuel injection to balance performance with fuel efficiency.With direct injection, fuel is delivered directly to the combustion chamber to create a more complete burn of the air/fuel mixture.Compared to a conventional port-injection system, less fuel is required to produce the equivalent horsepower, especially at normal cruising speeds.The Cobalt SS is rated at 260 horsepower and 260 pound-feet of torque, so we anticipate exciting performance.Chevrolet claims a quick 0-60 time of approximately 5.7 seconds, and the EPA-estimated fuel economy is a decent 22 mpg City/30 mpg Highway.

Chevrolet developed an all-new FE5 Sport suspension specifically for the SS, including upgraded stabilizer bars, spring rates and damper tuning, for a claimed cornering grip of 0.9 g.Front brakes are from Brembo and have a performance-oriented fixed-caliper design, which resists fade better than floating calipers.Rear discs are vented for better heat dissipation.This combination enabled the Cobalt SS to set a new class record of 8 minutes, 22.85 seconds at the famed Nurburgring racing circuit.

NewCarTestDrive.com correspondent Jim McCraw reported from Dearborn, Michigan, with Mitch McCullough reporting from Los Angeles and John F.Katz from Pennsylvania.