But a sports car with a back seat? That sounds interesting.

That's the premise of the Mazda RX-8 that goes on sale later this year. It's also the raison d'etre for the new Infiniti G35 Sport Coupe.

This isn't a new concept, of course. It's what automakers call 2plus2, a sporty car with at least the semblance of a back seat. But what makes the G35 coupe so special is that it emerges as the next good, new idea from the maker of two very good, very new cars.

Last March, Nissan's Infiniti luxury division put its G35 sedan on sale. Here was a pretty, fast, comfortable four-door car with a price tag under $28,000. Then, over the summer, Nissan brought back the Z. The 350Z was a pretty, fast, two-person car with a price tag under $27,000.

Those two models, which shared Nissan's FM platform and its 3.5-liter V-6 engine, ought to be enough for most buyers.

But, for the buyer who wanted to combine swoopy styling of the Z and the ability to carry four people like the G35 sedan, there required a different solution. That's the G35 coupe, a two-door car that seats four. It, too, uses the rear-wheel-drive FM platform and the 3.5-liter V-6.

Pricing for the G35 coupe starts at under $30,000. Even the base car is well equipped with a goodly number of air bags and other safety technologies, and plenty of amenities. Our tester was the top-of-the-line model, with leather seats and a six-speed manual shifter. Tossed-in options, including a sunroof and a 240-watt Bose stereo, took the car's window sticker to about $34,500.

Nissan executives insist the G35 coupe is neither a Z clone with a back seat nor a G35 sedan knock-off with two doors removed. I agree, if only because it's such a beautiful car that it deserves to stand on its own.

Even our test model, painted a ghastly shade called Caribbean blue, turned heads. The design is striking with balanced proportions, an aggressive front end, a nicely curved roofline and a well-defined derriere.

Sonny Osawa, Infiniti's chief product specialist, said the G35s have ''totally different'' sheet metal, and the coupe is shorter, lower and wider than the G35.

But, on the inside, the G35 coupe shares the look of the G35 sedan. Most notably, it gets the same tilt mechanism that lifts and lower both steering wheel and instruments to keep the speedometer and tachometer at perfect eye level. This is a good idea.

The front seats, specially designed for the more aggressive coupe, aren't as comfortable as those in the sedan, but they're more supportive during hard driving. The ones in back offer good shoulder room, but only adequate leg and head room.

The 3.5-liter V-6 continues to be one of the finest engines on the road today. Nissan uses it everywhere, from the Altima to its SUVs, but it shines most in cars like the G35 and 350Z. Engineers tweaked the powerplant's output to be able to produce different performance numbers for each model. In the 350Z, it's good for 287 horsepower and 274 pound-feet of torque. In the G35 sedan, it's 260 horsepower and 260 pound-feet of torque.

And, once again, the G35 emerges as a good compromise with 280 horsepower and 270 pound-feet of torque.

That power is controlled through a six-speed manual shifter that's quite nice. Until the coupe arrived, the sedan only came with an automatic transmission, but now it, too, has an available six-speed manual.

The driving experience is top-notch. This is a tight car that manages to remain comfortable. Handling, thanks to a strong suspension and big tires, is superior.

Infiniti says the luxury coupe segment has expanded rapidly recently, growing 48 percent from 1999 to 2001. About 145,000 sales were recorded in 2002.

Scott Fessenden, Infiniti's director of marketing, said the G35 coupe will compete against the Acura CL, the Mercedes-Benz CLK and BMW's 330 and 325 coupes.

Fessenden predicts the G35 coupe will sell 12,000 units in 2003. A typical buyer will be male (70 percent) and single (60 percent) with a median age of 37 and a household income of about $100,000.

Infiniti, the long-stagnant luxury division of Nissan, has been on quite a roll recently. Including the two G35 models, the brand has released four new cars in the past year. (The other two are the M45 sedan and the just-available FX45 crossover sport-utility.)

Product and price has been the key for Infiniti's new-found success.

Dave Burrows, director of Infiniti operations, says the division now sees itself as a ''performance-oriented, world-class luxury brand.''

Others are noticing, too. The G35s, both the sedan and coupe, were picked as Motor Trend's car of the year for 2003. The G35 also was among a trio of finalists for North American car of the year award. The 350Z was another, and the Mini Cooper was the third, and the winner.

I love the look and the driving feel of the G35 coupe, but what earned this car five stars in my book was its surprising practicality.

I took my two young sons up to go sledding in the Sierra while driving the G35 coupe. They fit nicely in the back seat, while their sleds fit (barely) into the car. One went under the hatch, while the other rode next to me in the passenger seat. Still, all our winter gear, and our lunch, and our change of clothes fit in.