The G35 gets more power for 2005, increasing its power advantage on nearly all of its competitors. Nissan's 3.5-liter V6 has been improved for 2005, starting with a more advanced variable valve-timing system. Airflow to the engine has been increased and key internal components strengthened, allowing higher maximum rpm. Output for G35s equipped with the five-speed automatic has increased to 280 horsepower, an improvement of 20 horsepower over last year's engine. Torque has been raised to 270 pound-feet (from 260). The V6 in cars with the 6-speed manual increases to 298 horsepower (from 280).

The G35 feels stable at high speeds and around fast sweepers. The driver feels well connected to the road. On winding roads, the G35 rewards the driver with quick, precise steering that offers good feedback. Drive it harder and it responds beautifully. It never surprises the driver with errant behavior, yet its chassis can be rotated or steered with the throttle through corners.

The available sports suspension includes special shocks and springs and P225/45WR18 summer tires. The G35 rides nicely with this setup, comfortable but firm. There's a bit of wind noise at 70 mph.

Granted, the G35 lacks some of the razor-sharp response of a BMW 3 Series, and the rear end bobs a bit in fast, sweeping turns, especially when the pavement is bumpy. But don't get us wrong: the Infiniti is clearly one of the best sports sedans in the class, offering better handling than any of the front-drive cars. The G35's long wheelbase, low center of gravity, aerodynamic downforce, and lightweight suspension are all designed to keep its tires on the road where they can generate maximum grip.

The G35's handling characteristics are designed to be less-fatiguing on the driver, a lesson Nissan learned in the 24 Hours of Le Mans, and in FIA Group C racing. Using a large-diameter tire instead of a wide tire makes the contact patch longer rather than wider for less noise and improved wet performance. Also, taller tires are less sensitive to camber changes and benefit from better sidewall support than a wider tire with a smaller diameter and shorter sidewalls.

For its part, the G35 coupe is supremely stable and offers great handling. It's precise, like a BMW, and firm, but has a nice ride. It feels like a high-performance sports car, not a sports-luxury car like the Lexus SC430. It jiggles on highway undulations, for example. Overall, it's a great balance. You feel connected to the road in the G35. It can be driven precisely at high speeds. It's very stable, perhaps more so than the Z.

The G35X all-wheel-drive sedan employs a system Infiniti calls ATTESA E-TS, for Advanced Total Traction Engineering System for All Electronic Torque Split. That alphabetic mouthful means that a computer controls an active center differential for smoother starts, better fuel economy, and better traction and maneuverability in snow. Most of the time, the system sends 100 percent of the driving torque to the rear wheels, so the G35X handles like a rear-drive sedan. (Many all-wheel-drive sedans are based on a front-drive system that biases more torque to the front.) Nissan's system will divert up to 50 percent of the power to the front wheels if it senses that the rear wheels are slipping. A Snow mode, selected by a button on the console, locks torque distribution at 50/50 front/rear, and reduces the sensitivity of the drive-by-wire throttle. This is the same all-wheel-drive system used in the Infiniti FX luxury crossover SUVs.

The G35's V6 produces a unique and sporty sound. There's lots of low-rpm torque, more than what's available from the BMW 330i, Mercedes C320, and Lexus IS 300. This makes the G35 feel very responsive around town. Stand on the gas and it delivers brilliant acceleration performance.

Shifting the manual gearbox is direct and precise though it requires a little deliberation. It doesn't feel as light as an Acura gearbox. But match the revs perfectly and you can shift without depressing the clutch pedal. This is no Solara or Accord coupe. The clutch pedal is relatively firm and takes more effort to depress than the pedal in a Toyota, Honda, or even a Porsche. This makes it more challenging to drive smoothly than those other coupes, harder to drive smoothly than a Porsche Boxster or 911.

The five-speed automatic transmission is super-smooth in normal use and quite responsive when pressed. It offers a manual mode, which can be activated by pushing the shift lever to the right, then back to downshift or forward to upshift. Some drivers find pushing the lever to the outside awkward, but we didn't feel it was an issue. Once in the manual mode, this transmission will assume you know what you're doing and are paying attention. If you select third gear, for example, the transmission will still automatically shift down to second when needed, but will not shift up to fourth; it will hit the rev limiter instead. This manual mode reduces the tendency for the transmission to upshift unnecessarily on winding, mountainous roads. It won't shift up when you lift off the gas to brake for the next corner; that gives you some engine braking when you lift off the gas, making your mountain climbing assaults more enjoyable. Still, the transmission is so responsive in the regular automatic mode, we tended to put it in Drive and leave it there.