Is a 2000 mustang gt faster than gt?

A 2000 Mustang GT is *a* GT. The question is comparing a specific year (2000) to the general class (GT). There's no other GT to compare it to without specifying the year and any modifications of the other car. Later model year Mustangs GTs are generally faster than a 2000 GT due to improvements in engine technology and other performance enhancements.