The 2000 GMC Sierra 1500 is available as a 2-door, 3-seat regular side. Starting at $16,300, the 2000 GMC Sierra 1500 SL 4x2 Regular Cab Short Box is powered by a 4.3L , 6 -cylinder engine mated to a manual transmission that returns an EPA estimated 17-mpg in the city and 23-mpg on the highway. The top of the line 2000GMCSierra 1500SLT 4x4 4dr Extended Cab Long Box , priced at $ 28,341 , is powered by a 4.8L , 8 - cylinder engine mated to an automatic transmission that returns an EPA estimated 15-mpg in the city and 18-mpg on the highway.