The 2000 celica GT uses the 1zzfe engine. That came with 5speed m/t. The 2000 celica GT-S uses the 2zzfe engine - YES, that came with a 6spped m/t. So which one you want . GTS - 7.2 seconds...GT, i'm assuming 8ish!
Edit: both are great cars, tge GT was your economy bottom of the lineup...very economical. The GTS - was your more 'enthusiast' car..the initial years for the GTS m/t were plagued with a lot of misshifting due to driver error..but the recent 2zz engines have that problem solved!