The biggest news for the 2012 BMW Z4 is under the hood. The normally aspirated in-line-6 is gone. Its replacement, a 2.0-liter turbocharged four, is the new entry-level face of BMW, providing the performance foundation for the new 5 Series, the upcoming 3 Series and this, BMW's performance roadster. With similar horsepower, more torque (!), lighter weight and better balance, this newest Z4 promises to recall any number of great drop-tops, some of which were built by BMW.