As an American whose family lives in Tampa, I am a Rays fan and despise the Red Sox. The Yankees are rivals - but I respect them. In addition, George Steinbrenner did a lot for the city of Tampa. The story was definitely for real and broke on ESPN here in the States at the same time. The idea is intriguing to me, but I can't really say what would happen.
I can see rooting against the Yankees and what they represent - but how can you not respect the Steinbrenner family's willingness to attempt to win the championship EVERY year? They are the class of the MLB and one of the most valuable sports franchises in the world. I get the sense that the Steinbrenner boys respect English football a helluva a lot more than the Glazers. I don't think it would go down that way, but I don't really want to find out either. The stadium would definitely get built, though. I guarantee that. And Spurs would become an even bigger global brand. Of course, we don't all really want that - do we? I think most of us like Spurs the way they are.
On a selfish note, maybe if they did get involved with the EPL the Yankees would suffer and the Rays might have a shot at the title...(we might just win anyway despite the evil empire's limitless bankroll)