The 2007 Jaguar XJ is available as a 4-door, 5-seat sedan. Starting at $63,585, the 2007 Jaguar XJ XJ8 is powered by a 4.2L , 8 -cylinder engine mated to an automatic transmission that returns an EPA estimated 18-mpg in the city and 27-mpg on the highway. The top of the line 2007JaguarXJVanden Plas , priced at $ 74,835 , is powered by a 4.2L , 8 - cylinder engine mated to an automatic transmission that returns an EPA estimated 18-mpg in the city and 27-mpg on the highway.