Repharim: That story is Bava Metzia 59b, if I recall correctly. And that has nothing to do with a Minhag. And I can guarantee you that it says nowhere in the SH”A that a person who comes to a new community has to change his Nusach Hat’fillah. I believe I recall seeing a T’shuvah which says the opposite of your claim, but I can’t recall where. I’ll look.
