get a KBB online estimate, using the "describe my car" feature. it's usually pretty close. I wouldn't "add money" to my car, but would take a "loss" of value on a used, owned car. Just my 10 cents. Good luck.
"The French soldiers are grand. They are grand. There is no other word to express it." - Arthur Conan Doyle, A visit to three fronts (1916)