The 2005 Buick LaCrosse is available as a 4-door, 5-seat sedan. Starting at $22,835, the 2005 Buick LaCrosse CX is powered by a 3.8L, 6-cylinder engine mated to an automatic transmission that returns an EPA estimated 20-mpg in the city and 29-mpg on the highway. The top of the line 2005 Buick LaCrosse CXS, priced at $28,335, is powered by a 3.6L, 6-cylinder engine mated to an automatic transmission that returns an EPA estimated 19-mpg in the city and 27-mpg on the highway.