New person here, engine replacement ‘00 Mustang

Are you looking for a "plug and Play" swap? If so, this isn't it.

A 2007 V6 is an Over head cam engine where as the 2000 V6 is over head valve (OHV). Bottom line. There's no way that a PCM from 2000 V6 will be able to run a 2007 over head cam motor.

Here's a thread where someone else attempted to fit a newer OHV motor into a 2000 MY. There's some detail on the problems with trying to swap a V6 with a split port intake into a model year that does not have one.

In addition be aware that half way through the 2000 MY, Ford switched the V6's from external balance to internal balance. Keep this in mind if mixing and matching parts from different MY's.

https://www.stangnet.com/mustang-forums/threads/97-v6-swap-to-01v6-help.902460/