OK, I think maybe I can shed some light on this. Let's look at it this way.
When is an old truck ruined? When it is no longer desireable.
3,4 and 5 are not ruined...Those are the ones we all want, period.
Now between one and two. I for one am not locked to pureism so I would rule out number 2 also. At least half the folk will want something modified if it is done in good taste.
That leaves us down to number one, and using my theory, if people (generally speaking, as in masses) want it, that means it isn't ruined. as for the poor truck that started this whole thing, based on the forum responses, I would consider it ruined. Some dreams that come to fruition are in fact works of art.
Thats the way I see it anyway.