The 2012 Buick LaCrosse is available as a 4-door, 5-seat sedan. Starting at $30,170, the 2012 Buick LaCrosse Base FWD is powered by a 2.4L , 4 -cylinder engine mated to an automatic transmission that returns an EPA estimated 25-mpg in the city and 36-mpg on the highway. The top of the line 2012BuickLaCrossePremium 2 AWD , priced at $ 37,040 , is powered by a 3.6L , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 16-mpg in the city and 26-mpg on the highway.