The 2010 Lexus IS 250C is available as a 2-door, 4-seat convertible. Starting at $40,610, the 2010 Lexus IS 250C (A6) is powered by a 2.5L , 6 -cylinder engine that returns an EPA estimated 21-mpg in the city and 29-mpg on the highway. The top of the line 2010LexusIS 250C(M6) , priced at $ 39,440 , is powered by a 2.5L , 6 - cylinder engine mated to a manual transmission that returns an EPA estimated 18-mpg in the city and 26-mpg on the highway.