Nissan knows as well as anyone the dangers in redesigning a popular car. Through the 1990s, it "improved" its Z-car until the bloated 300ZX carried virtually none of the charm (not to mention the sales volume) of the original 240Z. Nissan returned the line to its former glory with the 350Z, and has been rewarded with a brilliantly successful six-year run. And with the 2009 370Z, which is making its debut this week at the Los Angeles auto show, it has proved it has finally learned how to build on success.

The 370Z addresses every major complaint about the outgoing car - namely its weight and sub par interior quality - but maintains and, if anything, further distills the basic Z-car formula.

Powertrain

Not surprisingly, the improvements begin with a boost in power. The 370Z's heart remains the venerable VQ series V-6, but is the updated 3.7-liter unit from the Infiniti G37, making 332 hp and 270 lb-ft of torque. The most interesting update in the drivetrain lies, surprisingly, in the manual transmission. Whereas most sports car manufacturers of late have tried to make their slushboxes behave more like manuals, Nissan has updated its old-fashioned 6-speed with an automatic-like feature: downshift rev-matching. When a driver selects a lower gear and lifts up on the clutch, the 370Z will automatically respond with a blip of the throttle. The result is a perfect heel-to-toe shift - every time and for every driver. Of course, there will be a way to shut off this feature for those who can't stand even this bit of modern intrusion. And those who want to skip the clutch pedal altogether can opt for a new 7-speed automatic with manual mode and, for the first time in a Z-car, paddle shifters. With either transmission, Nissan says drivers can expect about a 2 mpg improvement in fuel economy compared to the 350Z, which netted 18/25 mpg with a manual (official EPA estimates for the new car have not yet been released).

Suspension

Perhaps more exciting than the gain in power and even the trick transmission is the reduction in weight. Nissan says the 370Z is about 90 lbs lighter than a comparably equipped 350Z, despite being more rigid throughout and meeting tighter (read: weight adding) safety standards. The secret to this accomplishment is aluminum. Nissan engineers used it extensively, including on the hood, rear hatch, and door skins. The 307Z is based on the same updated premium mid-ship platform that underpins the G37, and has new front sub frame made of, what else, aluminum. The control arm front suspension has been redesigned, and the multi-link rear is now stiffer and lighter than before. Despite all the changes and pound shedding, weight distribution remains unchanged at 54/46 front/rear. The 370Z also measures nearly four inches shorter than its predecessor, while gaining an inch in width.

The car retains Rays forged aluminum wheels, now standard, but ditches the 350Z's optional Brembo brakes for units of Nissan's own design.