The 2009 Infiniti QX56 is available as a 4-door, 7-seat sport utility. Starting at $55,050, the 2009 Infiniti QX56 4x2 is powered by a 5.6L , 8 -cylinder engine mated to an automatic transmission that returns an EPA estimated 12-mpg in the city and 18-mpg on the highway. The top of the line 2009InfinitiQX564x4 , priced at $ 58,150 , is powered by a 5.6L , 8 - cylinder engine mated to an automatic transmission that returns an EPA estimated 12-mpg in the city and 17-mpg on the highway.