I see no reason why you wouldn't just see the term through, assess the value of the car at the end of it and either temporarily borrow the settlement fee and sell the car privately or hand the thing back if it isn't worth any more than the balance figure privately (or borrow and keep it obviously).
You are going to take a bath financially in terms of the value the car has lost to this point or the changeover, why cause yourself any more hassle for a car you are happy with?
You are going to take a bath financially in terms of the value the car has lost to this point or the changeover, why cause yourself any more hassle for a car you are happy with?