When the now-redesigned Nissan 240SX rolled off the assembly line last summer, we were surprised by the transformation it had undergone. This new version blurs the fine line between sports cars and upmarket vehicles because Nissan has downplayed this car's racier lineage in favor of a more genteel and understated design.

All of this has been at the service of folks who favor graceful styling over road-burning performance, but who see themselves as too young to retire to a stately sedan. In short, the 240SX has been tweaked to cater to the changing values of the baby boomer generation - the first wave of which is now approaching the age of 50.

To that end, Nissan engineers have designed a more rigid body structure, extended the track and enhanced the suspension of the 240SX to ensure a more comfortable ride, easier handling and improved stability. Low to midrange torque has been increased to allow for smoother acceleration, and the suspension contact points have been made more compliant to reduce noise.

Inside, the old monoform seats have been replaced by cozier 2-cushion buckets, and the placement of controls, knobs and switches is more sensitive to the ergonomic needs of the middle-age driver than they were in years past.

That's not to say that the new 240SX is a cream puff. It still incorporates the nimble handling, spirited acceleration and styling accoutrements that made previous incarnations so popular to those buyers who harbor sports-car inclinations. It's just that some of the 240SX's sharper edges have been smoothed and rounded out for comfort's sake.

We tested the high-end, sporty SE model, which comes with numerous standard-feature amenities that include a sport-tuned suspension, front and rear spoilers, projector-style foglights, driver-adjustable lumbar support, moquette fabric seats with a sporty center insert, remote keyless entry with an anti-theft system, and attractive analog gauges with black digits on a white background.

Our test model was also equipped with optional anti-lock brakes (ABS), limited-slip differential and a sunroof. Including the destination charge, that upped the price of the SE to $23,163.

Standard equipment on both the base and SE models includes electronic fuel injection, front-engine/rear-wheel-drive powertrain, 5-speed manual overdrive transmission, power-assisted rack-and-pinion steering, independent strut-type front suspension and multi-link rear suspension, power remote-controlled mirrors, fold-down rear seatback, power windows and door locks, and dual airbags.

In a trendy sports-car climate where many vehicles favor pointed, wedgy or jelly-bean designs, the SE model of the 240SX possesses more horizontal lines that make the car look stately and dignified. The quarter panels are smartly sculpted, while the alloy wheels and stacked scoops of the front air dam suggest that the SE's comparatively tamer visage may be deceptive. The spoiler, fascias, mirror housings and recessed door handles are all body colored - so as to not clutter the SE's cleanly confident lines. Ditto the use of body-accent bead lines as opposed to more obtrusive side moldings.

To lend the redesigned 240SX an assertive look, the wheels were extended out toward each corner. Slightly wider and more low-slung than in the past, the 240SX also features a longer wheelbase. And to improve visibility, the front and rear roof pillars have been narrowed.

In the back, other drivers will definitely not miss the body-wide, wraparound taillights. The trunk, meanwhile, is roomy enough for three suitcases and four or five shopping bags.

The 240SX's comfort-plus design starts with traditional rump-hugging bucket seats - which are much more forgiving than the modular jobs of years past. And everything - climate control system, stereo, door locks, dome lights - can be reached without so much as a forward lean.

The analog gauges of the 240SX are laid out boldly and simply, but they borrow a page from the Nissan Maxima: During the day the dials are marked by dark digits on a white face; at night, the lighted digits illuminate a dark face.

Kudos to Nissan for employing simple graphic images to help the driver discern between the door-lock and window-lock buttons. The door lock is marked simply with the image of a key; the window lock is marked with an "X." The newly added square cupholder is recessed into the console - as opposed to extending out from it - thereby ensuring that your beverage is tightly secured. A small storage compartment provides enough space for up to eight cassette tapes.

In front of the rearview mirror, the single interior-light switch eliminates the head-scratching process of trying to figure out which button to push. The dome light over the driver's right shoulder can be engaged by passengers in the front or backseat.

Although much is right in the 240SX interior, rear riders had best be short: Legroom in the stern is negligible, though front-seat legroom is adequate, as is front-seat headroom. However, if you're inclined to don a chapeau in the winter, open the sunroof first to give yourself an extra inch or two of headroom.

According to Nissan research, the quality of ride is important to the 240SX's recently expanded target market. So the engine's valve timing and intake camshaft were tweaked to attain the aforementioned low to midrange torque that translates into velvety acceleration. Other changes - a more rigid cylinder head, revised engine mounts, a larger-volume exhaust system - reduce engine noise and vibration.

Meanwhile, various components of the front and rear suspension were modified to attain greater stability and maneuverability. For example, cornering ability and traction were improved by increasing the suspension stroke in the rear.

Such measures paid off handsomely. The ride of the 240SX is quieter and smoother, with greater ease of handling, than that of its comparatively gnarly predecessor.

Both on the freeway and in city traffic, our SE danced from lane to lane with minimum body roll and nary a disturbance to its passengers. It also negotiated an abrupt 90-degree,

25-mph turn with ease.

But Nissan's comfort-conscious refinements have not been made at the expense of performance: The 2.4-liter DOHC 16-valve 4-cylinder engine yields 155 hp at 5600 rpm. And the 160 lb.-ft. of torque at 4400 rpm - in a vehicle that is 80 lb. lighter than the '94 model - means the SE's

8-second 0-to-60 mph performance is a half-second quicker than it was in '94.

At 65 mph in the cruise control mode, the tach purred at a civilized 3600 rpm in fourth gear and an even calmer 2800 rpm in fifth. At 60 mph on the freeway, we gave it some gas and downshifted from fifth to fourth, and the SE delivered all the passing power we needed.

Braking power with the optional ABS was also impressive on our tester: In a light drizzle, our SE descended from 30 mph to a dead stop in less than 4 seconds.

No doubt, the gearheads will find something lacking in the Nissan 240SX's upscale move - and its accompanying emphasis on comfort over flash. But Nissan probably figures that offering four flavors of its awesome 300ZX road warrior is enough to satiate even the most rabid of racing enthusiasts.

For the rest of us, the graceful lines of the 240SX offer a dignified way to make sure that the transition into middle age is a relatively painless one.