In the automotive world, age is weakness, an opportunity for younger, fresher adversaries to move in for the kill. Take the Nissan Sentra. When the fifth generation of the budget sedan debuted in model-year 2000, it was hailed for raising the bar within the economy-car class with its sporty styling, long standard features list and fun-to-drive character. Six years later, the picture had changed. The once-victorious Sentra had become the vanquished, surpassed by rivals offering greater room and overall refinement.

A redesign was in order, and it's come with the 2007 Nissan Sentra. Built on Nissan's new "C" platform, this year's Sentra rides on a 6-inch-longer wheelbase, and it's also 3 inches wider and 4 inches taller. As a result, the cramped cabin of old has been replaced with accommodations that are downright spacious: The 2007 Sentra offers class-leading amounts of head- and shoulder room in the front seat, and there's finally real legroom for rear-seat passengers. The large 13-cubic-foot trunk features an innovative divider that can be used to facilitate hidden storage for valuables. Inside the cabin, a unique overhead compact disc holder holds up to eight CDs, and there are extra pockets and bins designed to hold MP3 players and cell phones. Last year's Sentra fell short in interior style and materials quality, but the '07 model has addressed that shortcoming with a sharp-looking cabin that belies the sedan's budget price tag.

Under the hood of the 2007 Nissan Sentra you'll find a 2.0-liter inline four-cylinder engine good for 140 horsepower. While this figure isn't exceptional, the 2.0-liter does offer 14 more hp than last year's 1.8-liter engine, and it provides acceleration on par with most competitors in this class. Transmission choices are a bit unusual for an economy sedan, as the Sentra can be equipped with either a six-speed manual (five-speeds are the norm in this class) or a continuously variable transmission (CVT). A conventional automatic transmission will not be offered. These transmissions carry over to the sporty Sentra SE-R models that arrive midyear. The standard SE-R has a 177-hp 2.5-liter four-cylinder paired with the CVT, while the hotter SE-R Spec V has a 200-horse version of the 2.5-liter coupled to the six-speed.

Nissan sedans typically offer sporty handling for their respective classes, but the '07 Sentra feels a bit tepid alongside its competition. It continues to use a non-independent torsion-beam rear suspension, which is cost-effective but provides less control through the corners than the true independent designs most of its peers use. Additionally, a switch to electric power assist for the steering contributes to better fuel economy but sacrifices feedback.

Upgraded running gear on the Sentra SE-R includes firmer springs and larger wheels and brakes. The SE-R Spec V goes even further by specifying a retuned and lowered suspension, complete with a thicker front antiroll bar and a V-shaped reinforcement brace in back. The Spec V also has larger front brakes and stickier summer tires. The SE-R retrofits result in a better-handling car, but even in Spec V form, the econosport Sentra lacks the spark of competitors in this price range. From behind the wheel, it comes across as heavy and distant as opposed to lightweight and engaging.

The all-new 2007 Nissan Sentra is no doubt a better, more refined car than its predecessor, with more capable engines and a more pleasant, flexible cabin. If you're looking for an economy sedan that'll give maximum interior room and versatility for your buying dollar, the Sentra is a solid bet. However, if inspired handling is your thing, you'll find your needs best served by the more athletic talents of the Mazda 3 or Honda Civic.

Buyers of the four-door, five-passenger 2007 Nissan Sentra sedan have a choice of five trim levels: base, S, SL, SE-R and SE-R Spec V. Standard on the base trim are 15-inch steel wheels, air-conditioning, a four-speaker CD stereo with an MP3 player jack, and power windows and locks. The S trim level adds 16-inch alloys, a height-adjustable driver seat, keyless entry, power mirrors, steering-wheel-mounted audio controls and an extra pair of stereo speakers. Step up to the SL trim and you get leather upholstery, a leather-trimmed steering wheel, keyless start, cruise control, an alarm system and a trunk divider.

The Sentra SE-R is equipped similarly to the SL, but the keyless start and steering wheel audio controls move to the options list. Additional standard equipment on the SE includes 17-inch wheels, firmer suspension tuning, larger brakes, a lower body kit, sport seats, aluminum-trimmed pedals, and oil pressure and G-force gauges. To that the SE-R Spec V adds summer tires, an even firmer and lowered suspension, and larger front brakes.

Options on all but the base Sentra include a sunroof, a spoiler, an upgraded 340-watt Rockford Fosgate sound system, Bluetooth, and either XM or Sirius Satellite Radio.

In base, S and SL form, the front-wheel-drive Nissan Sentra is powered by a 2.0-liter inline four-cylinder engine good for 140 hp and 147 pound-feet of torque. Base and S models are available with either a six-speed manual or a CVT designed to offer smoother operation and greater fuel-efficiency than a regular automatic. Sentra SL models come only with the CVT.

The CVT is also standard on the Nissan Sentra SE-R, which has 2.5-liter four-cylinder good for 177 hp and 172 lb-ft of torque. Slightly more frenetic in personality, the SE-R Spec V gets a high-output version of this engine capable of 200 hp and 180 lb-ft of torque. The Spec V's motor also has a higher redline (7,000 rpm versus 6,200 in the standard SE-R) and a preference for premium unleaded. A six-speed manual is the only transmission available on the Spec V, and it has an exclusive helical limited-slip differential option. Thusly equipped, the Nissan Sentra SE-R Spec V gets to 60 mph in 6.7 seconds.

Front-seat side airbags, full-length head curtain airbags and a tire-pressure monitor are standard on every 2007 Nissan Sentra. ABS is standard on the SL and both SE-R models, and optional on other trims. Four-wheel disc brakes are standard on the SE-R and SE-R Spec V, but all other Sentras have a front disc/rear drum setup.

Handling is adequate in the 2007 Nissan Sentra, though somewhat uninspired compared to the more visceral driving experience in the previous model. The car's electric power steering is well weighted, but there isn't much road feel. The SE-R models, particularly the Spec V, fare better in this regard and can be driven quite hard on a curvy road. The limited-slip differential is a worthwhile upgrade on the Spec V, as it enables the driver to tighten the car's line through corners. Compared to similarly priced peers, though, the SE-R Sentra feels a bit ungainly and fails to involve its driver as closely as we think a true sport compact should.

In the standard Sentras, ride quality is smooth and the cabin stays quiet on the highway. The SE-R models are similarly quiet, but ride quality suffers, especially on the Spec V. The standard 2.0-liter engine has adequate low-end and midrange power for easy city and highway driving, but tends to get noisy as rpm climbs. The SE-R models offer plenty of power throughout the range, and a tall 6th gear on the Spec V keeps the engine placid at highway speeds. At an 80 mph cruise, the 2.5-liter is parked at a comfortable 3,000 rpm.

The Sentra's cabin offers a modern, attractive design and agreeable materials quality. Accommodations are spacious, with ample head-, shoulder-, hip- and legroom for adults to get comfortable in both the front and rear. The cabin features lots of nooks and bins, as well as an overhead compartment that holds up to eight CDs. Luggage capacity is a respectable 13.1 cubic feet, and the trunk offers an innovative divider that creates a hidden storage place for valuable items. When more space is needed, the rear seats fold flat in a 60/40 split, so long as you don't mind folding up the seat-bottom cushions first. Note that the seats do not fold in the Sentra SE-R Spec V due to the encroachment of its rear chassis brace.