FAQ for
"Entourage" (2004) More at IMDbPro »

Yes, Turtle's real name is "Salvatore Assante"; it appeared way back in Season 3, Episode 11, where it was hidden under the box lid, in the graffiti art, on the Nike Air Force Ones that Fukiyama custom made for Turtle.

Also, in Season 5, Episode 11, "Play'n With Fire", he tells actress Jamie-Lynn Sigler, with whom he is starting a relationship, that his name is Sal..

Jerry Ferrara asked that Turtle's real name be "Sal" in tribute to a friend of his who died at a young age.

Yes, they are half-brothers. Which explains why they look nothing alike. They have different fathers. Which also explains the large age difference.

In the intro that appears before every episode, Turtle is driving the boys in a black, four door 61-69 series Lincoln Continental. It has widely been stated that the year of the car is 65'.

More info about the vehicle can be found here - http://en.wikipedia.org/wiki/Lincoln_Continental

It has been a running gag on the show that Drama is very old. For the most part his age has been left ambiguous, he stated in an early season that he was 36. But the dialogue of the scene suggested that he was lying. He also had mentioned that he drove Vince to see his first concert when he was 7, which prompted E to ask "You were driving when Vince was 7? How fuckin' old are you Drama?" However if this was supposed to be his character's age, it would place him at about 41 by the end of season 6. However, Kevin Dillon who plays Drama is 44 years old. So given that it's generally left unsaid we could assume he plays his actual age.

After Medellin flopped at Cannes, it likely marked the end of Billy's career. Or possibly because of how he handles criticism and rejection, he may have left the business on his own. But no studio would want to work with him after seeing Medellin. So his deal to make Silo/Lost in the clouds would have fallen through, as nobody would want to see a film that was written, directed, produced and starring the same people from Medellin.