The 2009 BMW Z4 is available as a 2-door, 2-seat convertible. Starting at $45,750, the 2009 BMW Z4 sDrive30i is powered by a 3.0L , 6 -cylinder engine mated to a manual transmission that returns an EPA estimated 19-mpg in the city and 28-mpg on the highway. The top of the line 2009BMWZ4sDrive35i , priced at $ 51,650 , is powered by a 3.0L , 6 - cylinder engine mated to a manual transmission that returns an EPA estimated 18-mpg in the city and 25-mpg on the highway.