I would say it's worth more then 15K
You can find a nice SC for 13-15 but it may need a clutch, head studs, top end rebuild etc and have over 100,000 miles.
Not too many black on black SC coupes in really nice shape are around either.
Also being owned by an enthusist is always a plus.
Price also depends on how quick you want to sell the car.
I would not let that puppy go.
