2009 BMW Z4 Roadster

First off, let's skip right past the part where we have to explain that the 2009 BMW Z4 Roadster is actually a hardtop convertible, complete with a two-piece aluminum roof that electrohydraulically deploys from the trunk in 20 seconds.

This new model takes the place of the former Z4 roadster and coupe models, and it'll be built in Regensburg, Germany, now that BMW's plant in Spartanburg, South Carolina, is devoted solely to X models.

The Z4 looks the same with its 98.3-inch wheelbase, but the hardtop model is slightly larger overall, now measuring 166.9 inches in length (5.8 inches longer), 70.5 inches in width (0.4 inch wider), and 50.8 inches high (0.4 inch lower).

Two engine choices are available. The 2009 BMW Z4 sDrive35i features the twin-turbo, 300-horsepower, 3.0-liter inline-6 with direct fuel injection, and you can choose either the conventional six-speed manual transmission or BMW's new seven-speed, dual-clutch automated manual.

The 2009 BMW Z4 sDrive30i has the normally aspirated, 255-hp 3.0-liter inline-6, and it gives you a choice between a six-speed manual and a conventional six-speed automatic. Both model designations include "sDrive," which is BMW's new nomenclature for rear-wheel drive.

BMW notes that the Z4 sDrive35i is actually quicker with the dual-clutch gearbox than the short-shift manual transmission, accelerating to 60 mph from a standstill in 5.0 seconds compared to 5.1 seconds with the manual. The Z4 sDrive30i gets to 60 mph in 5.6 seconds with its manual transmission and 6.0 seconds with the automatic.

The Z4 has BMW's Dynamic Drive Control as standard equipment, which allows you to select between three settings for the suspension and drivetrain calibration.

Electric-assist power steering continues, while there's a new brake combination with lightweight rotors and reduced brake pad wear, plus an electric parking brake.

The optional sport package features adaptive suspension damping. Both Z4 models have run-flat 17-inch tires as standard equipment, 225/45R17s in front and 255/40R17s in the rear.

As you'd expect with a hardtop convertible, there's a bit more luxury to the cabin, especially since the cockpit seems more spacious thanks to side windows that are 40 percent larger and a rear window that's 52 percent larger.