Be sure to check you local laws and regulations about this swap.
Even though your ST was built in March of 2000, it is considered a 2001 Model Year, and many states do not allow you to mount emission control devices, or engines, with a model year older then the vehicle it is going in. Just something to think about, as if that's the case, you may not be able to get the vehicle registered, insured, or pass inspection/emissions afterwards.