The 2003 Pontiac Bonneville is available as a 4-door, 5-seat sedan. Starting at $26,695, the 2003 Pontiac Bonneville SE 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 2003 Pontiac Bonneville SSEi, priced at $34,020, is powered by a 3.8L, 6-cylinder engine mated to an automatic transmission that returns an EPA estimated 17-mpg in the city and 27-mpg on the highway.