Hi Randall,
I am not going to comment about wether you should sell the car to give your kids the education that you and your wife want for them. I expect and assume you mean to give them the best you can and you have to make your own choices in that. In the end, as mentioned before, the NSX is a car, the others are human beings and your own flesh and blood.
However, it looks like a lot of importance here is put on the kind of school & education your kids will get at school. Since I don't live in the US I cannot comment on the quality and diversity of quality in US kindergarten, elementary and high-schools. The US educational system seems to be different from what I went through.
However, I would like to add the following.
I believe that the parents of children have as great or maybe even greater influence on a child's education and upbringing as a school. I have learned a lot of different things in school, reading, writing, math, geography etc. etc. etc.
But me having in interest in anything came from my parents. Me just WANTING to read books from the age of six up till today is something I got from my parents. My moral values, my principles, my tolerance for other people, other cultures, other ways of life, my indepence of thought, all these I learned from my parents and family.
Of all my interest that I have, from cars, old sailing ships, military) history, to computers, firearms, ballistics, music to the NSX, I have learned practically nothing in school. It was all my own doing, reading and listening to or reading about people who knew.
School-eduction will give a child (basic) skills like reading and writing. The interaction with other children will learn it how to function socially. But I think it's the parents that will teach a child morals and principles, to learn to say yes or no, to be independent and to make up your mind based upon what your child things and not to what someone else says. These things will not be taught at school.
Of course, as always, just my .02
