The 2003 Pontiac Grand Prix is available as a 4-door, 5-seat sedan. Starting at $21,760, the 2003 Pontiac Grand Prix SE is powered by a 3.1L , 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 2003PontiacGrand PrixGTP , priced at $ 26,410 , is powered by a 3.8L , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 18-mpg in the city and 28-mpg on the highway.