We know the Man City interest is serious (but we have ZERO to fear from their interest even if they bid 50m), but the others we dont know. For example, if (a big if) Perez will let Juande Ramos sign players according to his formation and football, which is 4-4-2, then I dont see Real going for him. They will go for wingers, and the bid on Ribery shows that. I dont think Real is an option. Paper talk like Inter is too.
But Chelsea, I have I'm not sure on wether or not they will go for him. But we should be able to compete with them, they dont go crazy on money anymore, and since Diego is our main target, we should invest heavily. Plus I think he prefers Italy for his career move as he said a bit.
IMO shouldnt be that big of an obstacle to get him if we invest the needed amount.