The 2020 BMW X3 M is available as a 4-door, 5-seat sport utility. Starting at $69,900, the 2020 BMW X3 M Base is powered by a 3.0LL , 6 -cylinder engine mated to an automatic transmission that returns an EPA estimated 14-mpg in the city and 19-mpg on the highway. The top of the line 2020BMWX3 MCompetition , priced at $ 76,900 , is powered by a 3.0LL , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 14-mpg in the city and 19-mpg on the highway.