The BMW Z4 comes with the option of a roadster with a convertible top or a fixed-roof coupe. The convertible comes in two trims: 3.0i and 3.0si. A 3.0-liter inline six-cylinder engine, six-speed manual transmission, 17-inch wheels, manually operated seats and vinyl upholstery come standard with the 3.0i trim. For the 3.0si trim, 18-inch wheels, a few upgraded interior features and a 255-hp 3.0-liter inline six are standard. The Z4 coupe only comes in 3.0si trim.The BMW Z4 is a carryover from 2006.