The 2018 BMW X3 is available as a 4-door, 5-seat sport utility. Starting at $42,650, the 2018 BMW X3 xDrive30i is powered by a 2.0L , 4 -cylinder engine mated to an automatic transmission that returns an EPA estimated 22-mpg in the city and 29-mpg on the highway. The top of the line 2018BMWX3M40i , priced at $ 54,500 , is powered by a 3.0L , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 20-mpg in the city and 27-mpg on the highway.