I hope for your sake then, that the Japanese version is better looking and better packaged. Not that the packaging of a game has ever had any influence at all in my purchase decisions before...
As for release dates - what do you consider the same date? Taken literally, I doubt that's going to happen. Even if the game itself was completely finished and regionalised (language, music, packaging etc.), the logistics of producing that number of copies for the entire global GT fan population...no chance. At best we'll get a gap of a couple of weeks, and more likely, a couple of months in the case of Europe. That's fine...I'd rather wait than fumble through Japanese menus. Even if the US got it a week after Japan, and Europe had to wait another two months or more, I'd still wait.