I agree with most here, if you buy it as an assortment of parts that might result in an operational car, I'd call it a "kit car". Various kits are more or less complete than others, and there are many independent businesses out there who will assemble your assortment of parts, as well as add whatever parts are needed to turn it into a functional automobile, for a price.
What irks me more than "kit car" is "...is it real?". Whenever asked that question, I offer to start the car up and have it move under its own power if that will convince the questioning party that it is real. What they more often mean is "....is it an original". Once we get to that point, I laugh and imform the questioning party that the few remaining originals (I drive a 427 Cobra replica) are too valuable to be driven on the street, almost impossible to insure b/c of their rarity, and that in all likelihood my "replica" (yes, I do use that term) probably performs better than the originals due to technological advances during the time since the originals were being produced.
I prefer the term "custom assembled replica".......just my own opinion, though.
Doug