2008 BMW Z4 M Roadster

BMW has always had a knack for making good things better, and giving the M treatment to the Z4 Roadster is a great example. Take the cutting-edge styling of the two-seat Z4 roadster, install BMW's smooth 330 horsepower inline six-cylinder engine, sport suspension, upgraded brakes, and racy sport seats and you've got a car that goes from the country club to the track racing club without missing a beat.

Known simply as the 'M Roadster,' this ragtop track car is only available with BMW's 3.2-liter inline six borrowed from the M3, putting out 330 horsepower at 7900 rpm and 262 pound-feet of torque at 4900 rpm. BWM uses a throttle-by-wire system which links fuel input to the engine control system, feeding fuel directly into each cylinder. The 'M Dynamic Driving Control' allows the driver to switch from a quick response for spirited driving to a normal response for more fuel-efficient and smoother street driving.

Weighing in at just over 3000 pounds, the car is quick off the mark and fast in passing conditions. The flat torque curve provides rapid acceleration at any speed, making the car confident in traffic and capable of snapping off a quick pass in any gear.

Appropriate to its track use, it comes standard with BMW's satisfying six-speed manual transmission, vented cross-drilled brake rotors (13.7 inches diameter in front, 12.9 rear), and sport suspension on 18-inch alloy wheels with 225mm front tires and 245mm rear tires. Track is wider on the M Roadster, and suspension and steering gear is modified, compared to the standard Z4 give what BMW calls 'beyond exceptional' reflexes.

A track-tuned dynamic stability control and M Variable Differential Lock provide largely unobtrusive assistance to keep the driver from getting into trouble if, for instance, the pavement surface traction changes abruptly. Though the sports suspension provides responsive and satisfying handling, especially on smooth track surfaces, reviewers note that the ride quality suffers on normal freeway pavement.

The once-controversial blade-edged BMW styling is now familiar, having been introduced on the Z4 roadster in 2003. The fully-automatic soft top is lined for sound insulation and weather protection, with a heated glass rear window. A removable hard-top is available as a dealer option.

On the interior, the fat steering wheel and special 'M Seats' with supportive side bolsters, in premium Napa leather, is perfect for track driving and enthusiastic backroads curve-carving. Space inside, however, is cramped and the trunk has half a cubic foot smaller than the Z4 because of space needed for the soft top mechanism and the Mobility Kit (which substitutes for a spare tire). A long list of luxury options is available, including BMW's Premium Package with upgraded audio, extended leather, nav system, and HD radio.

Safety features include dual front impact Smart Airbags, automatic seat-belt tensioners, side impact airbags, and Advanced Crash Safety Management. Fixed hoops behind the seats protect occupants in the event of roll-overs. BMW Assist teleservice with GPS locator and hands-free communications for emergency and other services, including automatic collision notification, is standard.