Possible to do this?!!?!?
You say this Mustang is on the Budget lot? Was it a rental car before? If so, how many people rented it in the last 2.5 years and smoked its poor rental car tires? How many miles? How many different people abused it in how many different ways? Risky, risky... those rental sports cars.
The Scion tc is new right? Yours free and clear. No mishaps so far? Trouble free. It may not be the status symbol of your dreams, but it IS the better bet. Lightyears more reliable, and still under full warranty.
Nah, I'm not going to bash you. I've simply gotten used to playing for larger stakes... and longer games. The Scion is a more than enviable start! Keep it through college. Trade it for the real toy when you strike off on your own.
Besides, politically, your parents may not ever tell you, but its gonna hurt some feelings if you pawn off their gift. Its a large gift! Besides... could have been worse... they could have gotten you an Xa.