The 2006 Maserati Quattroporte is available as a 4-door, 5-seat sedan. Starting at $103,700, the 2006 Maserati Quattroporte Base is powered by a 4.2L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated 12-mpg in the city and 15-mpg on the highway. The top of the line 2006 Maserati Quattroporte Sport GT, priced at $112,200, is powered by a 4.2L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated 12-mpg in the city and 15-mpg on the highway.