Well let me tell you this first. My dad makes 6 figures a year without bonuses, and I'm getting a ford focus (a used 2008 hopefully) and I realized that even though he's sometimes been a crappy father and I feel that it's he owes me a car, he really doesn't. So I don't think you should expect that of your father.
a) It's a convertible, in the winter if it's cold, your car will never warm up, I road to school with my best friend last year and she has a convertible bug, it's froze us to death.
b) It's a mustang, insurance on a 16 year old will eat you alive. Roush's are usually a V8, which is far to much power for a first driver.
c) you are 15, you don't need a car until after you have your liscense.
d) it's 16,000 bucks..you can get a 2008 mustang
convertible used for that.
e) You don't need that specific car, if your dad is willing to spend that much, than you should be greatful and let him pick the car..or both of you come to a compromise.
f) they are RWD they don't go in snow, you'd have to garage it in the winter, or wreck basically.