Three main flavors of the 2014 BMW Z4 are available: sDrive28i, sDrive35i, and sDrive35is. The first gets a turbocharged, 2.0-liter four-cylinder engine rated at 240 horsepower. The second rates 300 horsepower and 300 pound-feet of torque from a 3.0-liter in-line turbocharged six-cylinder powerplant. The sportiest version is the third, extracting 335 horsepower and 332 pound-feet of torque.
As you'd expect, performance matches the engines: the base model is quick and fun, managing the sprint to 60 mph in as little as 5.5 seconds per BMW, but lacks the ultimate force and vigor of the two six-cylinder models. For those wanting a measure of efficiency with the luxurious sports roadster, however, the four-cylinder turbo sDrive28is is hard to beat. Moving up to the sDrive35i cuts 0-60 mph times to as little as 5.0 seconds, but also bringing a significant improvement in in-gear acceleration at any speed. The sDrive35is takes performance up yet another notch, hitting 60 mph from a stop in just 4.8 seconds and delivering even more responsive acceleration.
For the sDrive28is, a six-speed manual transmission is standard, and it's a great choice if you like to do your own gear changes. It's a slick, low-effort shifter that never gets in your way. An optional eight-speed automatic also provides quick and smooth shifts, though it leaves the car feeling somewhat less spirited. In the Z4 sDrive35i, the six-speed manual is also available, but the eight-speed auto is replaced by a seven-speed dual-clutch transmission. Quick-shifting and easy to use with the steering-wheel-mounted paddles (or left to its own devices in automatic mode), the dual-clutch gearbox offers the best of both manual and automatic worlds. BMW's dual-clutch in the Z4 is of an older school, however, and doesn't match the race-inspired crispness or near-telepathic logic you'll find in Porsche's PDK dual-clutch, offered in the Z4-rivalling Boxster. The sDrive35is is only available with the seven-speed dual-clutch transmission.
Handling is good across the Z4 range, particularly when equipped with the optional M Sport Package (which is standard on the sDrive35is). Cornering is confident and quick, with direct, if not intuitive steering, and BMW's typical sense of feel only slightly muted from its more hardcore M Division vehicles. With the M Sport Package, the Z4 looks and feels much more like its M cousins, with the Adaptive M Suspension doing the bulk of the work in improving handling. Upgraded 18-inch alloy wheels with performance run-flat tires also improve grip, though the choice of run-flat tires does nothing for ride quality.
Whichever Z4 model you choose, you'll get a balanced, controlled chassis riding on an adjustable Driving Dynamics Control suspension system that offers Comfort, Sport, and Sport+ settings. Dynamic stability control with traction control, brake fade compensation, start-off assist, brake drying, and brake stand-by features offer high-tech aids to improve driving safety and consistency.