Now entering its fourth year of production, the midsize Pontiac G6 continues on a course of steady improvements catering to the performance-oriented and style-conscious sedan, coupe or convertible shopper. Following significant power and mechanical upgrades last year, changes to the G6 for 2008 focus primarily on updated cosmetic details and additional standard safety equipment.

Pontiac is ballyhooing its new GXP trim level for the G6 sedan and coupe -- a designation that helps tie the car into Pontiac's branding nomenclature. But in actuality, it's little more than a new name for last year's high-line GTP model, with the exception of the GXP Street Edition coupe that adds gaudy bodywork and a huge "hammerhead" spoiler. Lesser G6s benefit from newly standard features like front side-impact airbags, antilock disc brakes, OnStar communications and satellite radio for the upper trim levels.

The Pontiac G6 shares its basic body structure with the redesigned Chevy Malibu and Saturn Aura. Of this group, the G6 is the only model to come in three body styles. The convertible features a retractable hardtop design and is one of the few such vehicles offered with a starting price of less than $30,000. This feature is enjoying increased popularity of late, and it's easy to understand why, as a retractable hardtop promises the security, styling and quiet of a coupe with the top in place. In the G6, the top-down transformation takes less than 30 seconds at the touch of a button. This opens up a backseat that's roomy enough for two adults, but with only 2.2 cubic feet with the top lowered, good luck fitting anything larger than a pizza box in the trunk once it's pressed into service stowing the retracted lid and attendant mechanism.

While the convertible may be the style leader, the G6 coupes and sedans also offer their own distinctive, well-adorned appeal in the midsize class. But a few minor things hold the car back, such as lackluster interior materials. The 2008 Pontiac G6 is worth a look, though models like the 2008 Honda Accord and Nissan Altima might prove more satisfying to own overall.

The 2008 Pontiac G6 four-door sedan is available in four trim levels: the entry-level Value Leader, base G6, GT and GXP. Coupes are clad in either GT or GXP trim, while the convertible is offered only as a GT. The G6 Value Leader sedan comes with 16-inch wheels, air-conditioning, fully powered accessories, a four-way manual driver seat with power height adjustment, a 60/40-split-folding rear seat, a tilt/telescoping steering column and CD player with an auxiliary audio jack. The more upgradeable base G6 adds 17-inch alloy wheels, cruise control and remote keyless entry. The midlevel GT comes with V6 power, a sport-tuned suspension, a leather-wrapped steering wheel and shifter, and an eight-speaker Monsoon sound system with a subwoofer and satellite radio.

Fully loaded GXPs further upgrade to 18-inch chromed wheels, a rear spoiler (sedan only), automatic climate control, auto-dimming rearview mirror, a six-way power driver seat and heated front seats. Some of these items are also available on lesser G6s. Other notable options include a remote starting system and power-adjustable pedals. Available equipment packages group together these and other premium features like leather upholstery, an in-dash CD changer and a sunroof. The new GT and GXP Street Edition packages also lend their own distinctive performance-inspired bodywork.

All Pontiac G6s route their power through the front wheels. The basic Value Leader and G6 sedans come equipped with a 2.4-liter four-cylinder that produces 164 horsepower and 158 pound-feet of torque. Standard in the GT and optional in the G6 sedan is a 3.5-liter V6 putting out 219 horses and 219 lb-ft of torque. Convertibles with this V6 have slightly less power at 217 hp and 217 lb-ft of torque. Both of these engines are attached to a four-speed automatic transmission.

The performance-driven GXP models are equipped with a 3.6-liter V6 that generates 252 hp and 251 lb-ft of torque. It's mated to a six-speed automatic with manual-shift capability. Convertibles with the optional 3.9-liter V6 check in with 222 horses and 238 lb-ft of torque. EPA-estimated fuel economy for the four-cylinder and V6 engines is mostly on par for the midsize segment, though the convertible's optional V6 is thirsty, with a 15 mpg city/22 mpg highway rating. In performance testing, we found that a GXP coupe could accelerate to 60 mph in a quick 6.2 seconds.

Four-wheel disc brakes with ABS are standard on all 2008 Pontiac G6s, as is integrated traction control except for GXP and convertible models with stability control (optional on GTs). Full-length head-curtain and front side-impact airbags are standard on all G6 coupes and sedans, and convertibles feature standard front seat-mounted side-impact airbags. In government crash testing, the G6 sedan and coupe earned a best-possible five-star rating for driver protection in frontal impacts. Front passengers have a four-star rating. Side-impact testing in a G6 sedan resulted in five stars out of five for both front and rear passengers. In Insurance Institute for Highway Safety crash testing, the G6 sedan and coupe received a top score of "Good" for frontal-offset impact protection; that agency's side-impact tests resulted in a second-highest "Acceptable" rating. Convertibles fared less well, with an "Acceptable" score for frontal-offset impacts and a lower "Marginal" rating for side impacts.

Our only real gripe continues to be the numb-feeling electric power steering on the Value Leader and base G6 sedans -- the hydraulic power steering included on GT and GXP models (and optional on the standard G6) is much more communicative and to our liking. All G6s deliver surprisingly athletic ride and handling, which is dialed in even tighter in the firmly tuned GT and GXP. These sportier models are fun to drive, delivering flat and composed cornering with a minimum of body motion when pushed aggressively through the twisties. The fuel-efficient 3.5-liter V6 delivers plenty of low-end torque for quick acceleration and easy passing, but it also gets a bit raspy at higher engine speeds. As expected, the GXP offers the most performance and sophistication for enthusiasts with the 3.6-liter V6's impressive output and manually shiftable six-speed automatic.

For a nose-heavy front-driver, the 2008 Pontiac G6 convertible is an adequate handler. But uneven city streets can cause the G6 to hop and float the way cars from the 1970s once did. What's more is that despite the "S.S. Pontiac G6" feeling, there's still a noticeable amount of cowl shake and shudder when driving over rough pavement.

The Pontiac G6's highly styled seats feature prominent side bolstering to keep you in place during hard cornering and aggressive maneuvers. The gauges light up with Pontiac's signature red glow, and reside in an attractive and brightly ringed cluster. The cabin features lots of chrome and faux metal accents to brighten things up, but the quality of materials on the dash and console is a notch or two below class standards. If that doesn't bother you, there is plenty of room provided by the car's long wheelbase, which results in generous rear-seat accommodations whether your G6 is a coupe, sedan or convertible.

With the touch of a button on the windshield header, the convertible's two-panel roof folds and stows quickly and quietly beneath a hard tonneau cover in about 30 seconds. Once it is stowed, luggage capacity shrinks from an already tight 12.6 to a miniscule 2.2 cubic feet. All that folding metal has to go somewhere, and with rear-seat accommodations an obvious priority, the trunk suffers. Sedans have a 14-cubic-foot trunk with a fold-down rear seat.