BMW has taken the wraps off the second-generation Z4 (third if you count its Z3 predecessor), and we like what we see. Big changes include the addition of a retractable aluminum hardtop, a major bump in horsepower and an increase in length of almost six full inches. The "entry-level" BMW Z4 sDrive30i delivers 255 horsepower, while the twin-turbocharged Z4 sDrive35i offers up 300 horses. Those figures represent bumps of 40 and 45 horsepower over their respective predecessors. Six-speed manual transmissions are standard, while the sDrive 35i offers BMW's new seven-speed, dual-clutch automatic. So equipped, BMW claims the Z4 is capable of scooting to 60 miles per hour in 5.0 seconds. The sDrive 30i is available with a more conventional six-speed automatic. Even though BMW has replaced the outgoing model's soft top with a retractable hardtop, the Z4's trunk will swallow a full-size golf bag with the top down, and two with the top up.