Sounds like you want him to buy the car
YOU WANT not what he wants cause you want to drive it
NOW. Sounds kinda selfish actually.. Let him buy the roadster. After contemplating the bloodbath he's facing to put you through college, he needs to make one happy decision. Maybe it's his time for a roadster. You're not giving up much per this test:
2010 Nissan 370Z Roadster Full Test and Video on Inside Line
YOu can drive it on Christmas break, but if you were my kid, I'd be reluctant.....