if he wants to buy the car, let him buy the car. if he's smart, he'll make the right decision. if he's dumb, he'll lose his money like dumb people deserve to.
if you're buying a car just to pull a girl or to fit in, i feel sorry for you. if you're buying the car b/c you always dreamed of owning one like that and set goals in life to get to the point where you could buy the car, good for you. nothing wrong with rewarding yourself. but bragging about it and looking like one of those old guys in a porsche jacket, a porsche hat, a porsche shirt, and a porsche tattoo is pretty damn pathetic.