Twin-turbos, meet cyber-tranny
Under the tester’s hood was one of the hottest new couples in the industry: BMW’s silky 3-litre twin-turbo straight-six teamed up with a 7-speed, dual-clutch, paddle-shift transmission. This optional gearbox sends the engine’s 300 horsepower and 300 lb.-ft of torque to the rear wheels in a continual, uninterrupted flow.

Under the tester’s hood was BMW's silky 3-litre twin-turbo straight-six.

Dial up the gearbox’s most aggressive shift setting, and you’ll be treated to a reedy blurp from the exhaust during the split-second upshifts. Call up some downshifting and the gearbox blips the throttle for exceptionally smooth rev-matching. The dual-clutch transmission enables fingertip control of an assortment of melodious sound effects.

This robotic transmission is priced at just $1,950. That’s plenty cheaper than Porsche charges for their comparable ‘PDK’ unit, which doesn’t have selectable shift settings.

The electronic throttle walks the car off the line when jammed, though the turbos get to work shortly thereafter in a serious way. It’s not only the thrust, but also the engine’s character that threatens your driver’s license here. Firing off computer-enhanced gear changes is plenty fun, but the engine loves to rev and sounds beautiful in the process. It’s a heck of show-- but it’s also very easy to get carried away with.

Keep your right foot in check, and combined mileage should average about 10L / 100km. Note that the Z4 has a non-turbo engine and six-speed manual available, if you’re after something a bit more modest.

A mixed bag for the ride
Though Z4 proves comfortable and relatively quiet on smooth highways, the optional 18-inch alloys with 30-series rubber can become downright jarring. With little give in the suspension and sidewalls, these wheels can cause the Z4 to pound alarmingly over rough roads, especially during acceleration. Consider them only if you’re locale has roadways in above-average condition.

With little give in the suspension and sidewalls, these wheels can cause the Z4 to pound alarmingly over rough roads.