I think Borriello's competition are Gila, Toni, & Amauri while Pazzini has different attributes since he does not have the physique to play the role the others can play but he is definitely a better finisher.
I'd say Amauri's form these last 2 seasons shouldn't even make him an option but following Lippi's speeches since forever now, he will consider him. I agree that Toni has a lot to do, but at least now he has given himself a chance, and he has also been a Lippi favorite since the last WC. So i guess Gila is the main rival and is obviously ahead in Lippi's book, so Borriello knows he still has a lot to do which is sg positive for us
As for Ambrosini, i am sure that if he continues like that he will go to the WC ahead of Gattuso, Palombo, Galloppa... the only certain player here is De Rossi...and rightly so