The phrase "do to a T" means to do something perfectly or without any mistakes. There are several synonyms that can be used in place of this phrase. One alternative is "execute flawlessly," which implies that the task was completed without any errors. Another option is "perform with precision," which suggests that the task was done with great accuracy. "Accomplish faultlessly" is another replacement for "do to a T," and it indicates that the task was completed with impeccable quality. Other possible synonyms for "do to a T" include "perfectly execute," "flawlessly achieve," and "meticulously complete".