BMW Introduces Z4 M-Roadster and Updates Rest of Z4 Range for 2006

As with the past M-Roadster, the new car's exterior changes are understated. Visual mods include a new front valance stylized

Z4 M-Roadster visual mods include a new front valance stylized after the M5's air-splitter, while in back the bumper integrates quad pipes and a downforce-inducing rear diffuser. (Photo: BMW Canada)

after the M5's air-splitter, while in back the bumper integrates quad pipes and a downforce-inducing rear diffuser. A 10 mm (0.4 in) drop in ride height over comparable models, and 18-inch alloy wheels round out the exterior treatment. Minor revisions to the car's body mean that it is 22 mm (0.9 in) longer, 3 mm (0.1 in) higher and rides with 2 mm (0.07 in) extra between its wheels, but track and width remain constant.

Under its sharkish snout, the M-Roadster is powered by the existing 3.2-litre inline-six from the current M3, not the next-gen 400-hp 4.0-litre modular V8. Outputs in power and torque are unchanged at 343-hp and 269 lb-ft (European specification), but placed in the Z4's vastly lighter frame it makes

The M-Roadster is powered by the existing 3.2-litre inline-six from the current M3. (Photo: BMW Canada)

for an increased power to weight ratio of 241 hp/tonne compared to the M3's 218 hp/tonne. Zero to 100 km/h acceleration time is five seconds flat, with an electronically-limited top speed of 250 km/h (155 mph).
 
But just because the M-Roadster doesn't debut BMW's latest technology doesn't mean it's not a credible sports car. Engineers have worked to make it one of the most complete sports roadsters to date by reworking the M3's six-speed manual gearbox with a shorter final drive to improve in-gear and overall acceleration. Also included is the M3's M-Variable locking differential, which has the unique ability to control power distribution by locking the rear axle for improved traction in all road conditions. Seeing as this is a true enthusiast product, the six-speed SMG sequential gearbox is not offered.