Do you care what your car is worth?
I dont think of my car as an investment.
I will have way more into it than its worth. As long as i get seat time to repay my dollars and sweat equity i will be satisfied.
But i will have a rough idea what i put into it,because someone may want it more than i do.
If i was building it to sell,i would close my shop to outside work and and lose my shirt in the process. There is no money in this type of project.