I like "scratch built." Another term may be "manufactured." They are all manufactured. The parts are bought someplace or produced and put together by someone or some group.
"Kit" has a put down quality to it: "Oh, that is a kit car." Typically the speaker may only have enough automotive knowledge to maybe change their
oil, if that.
As for car shows, I go to meet and talk wth people. How the car is classed and if it gets a prize or not is a car show problem, not mine. I have a car that is fully unique and gets lots of attention from lots of people lots of the time. It is in a class by itself. Competition against other cars is an apple to orange comparision anyway. So if they wnat to put me in the "fruit" class and the judge prefers pears instead of apples or oranges, it does not bother me in the least. The car does not need the validation of a judge provided it meets my standards.
Cobras get respect. Most of the time, the "putdowns" are from people being self-defensive or envious.