Are you talking about selling the car to a private buyer or a dealership?
I'd say it really depends on the timing and the buyer. Right now is probably not the best time to sell your Cobra - winter is coming and many are putting theirs on sale considering it can't be driven for good 4 months. Wait until the Spring if you can, you'll get more money out of it.
Eh, I'd avoid carmax. They tried to short me BAD on my redfire vert. They offered me like 3k below KBB TRADE IN value. Just sell it on your own, you'll be better off.