The 2009 Porsche Boxster is available as a 2-door, 2-seat convertible. Starting at $46,600, the 2009 Porsche Boxster Base is powered by a 2.9L , 6 -cylinder engine mated to a manual transmission that returns an EPA estimated 19-mpg in the city and 27-mpg on the highway. The top of the line 2009PorscheBoxsterS , priced at $ 56,700 , is powered by a 3.4L , 6 - cylinder engine mated to a manual transmission that returns an EPA estimated 19-mpg in the city and 26-mpg on the highway.