Roazir; Fars is the Arabic version of Pars, the Iranian name when translated to English is “the Gulf of Pars” and the English name “Persian Gulf” means exactly the same thing, Interestingly enough most Gulfs in the world are called like the Iranian name for e.g. Gulf of Mexico, Gulf of Aden, Gulf of Carpentaria, Gulf of the Farallones, Gulf of Maine, Gulf of Tonkin, Gulf of Guinea, etc, etc, so the correct name for the Persian Gulf should have been “the Gulf Of Pars” just as the Iranian name is! 

As for the Azarbaijan, as both versions already exist on the Wiki and we are not inventing a new name, I insist on using the one that is recognised by the majority of the people in the region. The whole population of Rep Azerbaijan is less than 10% of the population of Iran (let alone other countries in the region who write and pronounce the word  Azarbaijan like Iranians do) so why a vast majority should follow a small minority? It is Azarbaijan and English speaking people better get used to it!