The BMW Z4 is a two-seat convertible with a retractable hardtop, offered in three trim levels—each with a different engine—the BMW Z4 sDrive28i, Z4 sDrive35i, and Z4 sDrive35is. So what is sDrive and the reason for the long nomenclatures? All BMW models used to be rear-wheel drive, so there was no need to differentiate. But when BMW began offering all-wheel-drive models, they named those xDrive. Now, to call out rear-drive models, BMW has selected the sDrive nameplate in addition to the original series/engine-displacement nomenclature.

For starters, the 2012 BMW Z4 sDrive28i is new for this model year and replaces the sDrive30i. It’s powered by a new, turbocharged, 240-horsepower, inline four-cylinder engine. Standard features include 17-inch wheels, auto and adaptive Xenon headlights, Bluetooth, height-adjustable seats, and more. The 2012 BMW Z4 sDrive35i and 35is models add a 300-horsepower 3.0-liter inline six-cylinder engine. The 35i adds such standard features as dual-zone climate control, leather seating, and eight-way power-adjustable seats.

2012 BMW Z4 sDrive35is models add a unique version of the M Sport front fascia, with trim bars in the outer air intakes, and wider spacing between the slats in the signature twin-kidney grille. Along the sides, it has unique 18-inch wheels and oxide silver mirror caps; exclusive 19-inch wheels are offered as well. At the rear, it features the M Sport bumper and a body-color lower fascia with modified exhaust surrounds.