The V6 engine in our 3.5SL makes a potent 270 horsepower, being a very close relative to the 3.5-liter V6 in the Nissan 350Z sports car, and we used much of it on this road. There's more than enough; in fact it's awesome for passing. Redline 6600 rpm is a blast. There's also 258 pound-feet of torque, which was very useful with the new CVT transmission.

The suspension has been redesigned on the new rigid chassis, and it passed this difficult test with flying colors. It's quite firm; there's no swaying in the switchback turns, so the steering stays true. And it wasn't harsh over the jagged parts of the road. It took some good punches from potholes, without flinching.

The electric power steering, speed-sensitive rack-and-pinion, works well, and because it uses less power than hydraulic, it improves gas mileage by a touch. The Altima 3.5SL doesn't quite feel like a sports sedan, but the handling is fairly nimble.

The engine has been lowered in its cradle for better balance, and there have been changes to the steering geometry that lead to breakthroughs in reducing torque steer, that disconcerting effect in a front-wheel-drive car whereby the steering wheel twists when you stand on the gas. Engineers have worked with kingpins and half shafts, and believe they have raised the bar for other powerful front-wheel-drive cars. Indeed, the torque steer in the Altima is extremely mild, which is saying something for 270 horsepower.

But the real engineering breakthrough might be with the CVT, or continuously variable transmission. This is the fourth generation of this transmission design, which doesn't have the separate gears of a standard automatic transmission, and Nissan has been a standout in this technology. The Sentra's CVT, for example, has just two ranges. But the CVT in the Altima has a manual mode, which, in effect, makes the transmission a six-speed.

We love it because it's true to us. It's totally responsive and obedient. It did things that the manual mode in some expensive cars (Mercedes and BMW, to name two) have apparently never dreamed of. It listened to the driver. We challenged it by upshifting all the way up to sixth gear at no more than 30 miles per hour, then downshifting back down, and it made every shift instead of ignoring them, unlikely as they would have been under regular driving conditions.

So, when we used it in the real world, shifting the Altima like a 350Z on the road to Stinson Beach, it was beautiful. And you still get the fuel efficiency of a CVT: 22 city and 28 highway miles per gallon (premium fuel required) with the powerful V6 (26/34 with the four-cylinder). Downshifting with the CVT to slow down worked well, combining with the good brakes when rushing up to those downhill curves. The brakes are vented discs in front and solid in rear.

We drove a 3.5SE with the six-speed manual gearbox, and the linkage didn't feel exceptional, which makes the CVT seem especially like the best of both worlds.

We also got some seat time in a 2.5S, with the 175-hp engine, and it felt like it had plenty of power.