The 2000 GMC Sierra 2500 is available as a 2-door, 3-seat regular side. Starting at $21,271, the 2000 GMC Sierra 2500 SL 4x2 2dr Extended Cab Long Box is powered by a 5.7L, 8-cylinder engine mated to a manual transmission that returns an EPA estimated The top of the line 2000 GMC Sierra 2500 SLT 4x4 4dr Extended Cab Long Box, priced at $30,556, is powered by a 6.0L, 8-cylinder engine mated to an automatic transmission that returns an EPA estimated