Pushing a healthy 330 horsepower and propelling this drop-top to 60 mph in less than five seconds on the way to an electronically-governed 155 mph, the 2007 BMW M Roadster’s 3.2-liter inline six-cylinder engine is lifted directly from the M3. The standard transmission is a six-speed manual, though a six-speed Steptronic automatic with paddle shifters will be available.