Some 'enthusiasts' seem to replace almost the whole car.
When does a classic car cease to be the original?.......and therefore worthless.
When does a classic car become Trigger's broom?
That seems to happen a lot in many restoration projects of various types.
During my days assisting in the restoration of standard gauge steam railway engines I noted how many parts came from other engines of the class (a process typical in all engine repair and maintenance sheds of the great days of steam) as well as new parts being fabricated by some very clever engineers and supplies of today.
When you looked at many ex-Barry scrapyard engines that had been fully restored, you were actually looking at, say, an engine which was a collection of parts from 1928, 1930, 1935, 1948, 1960, 1978, 1990, onwards!!
So it is, I believe, with many motor vehicle restorations. A collection of parts, but still all with it's "history" contained within it's whole, which for me is perfectly valid