Buying that old GTS you listed earlier would be only worthwhile as a labor of love. You will never get what it costs to restore it in return. If it were a 440 car...maybe.
With my car, I bought it at a good price and finished the restoration making what I have in it and what it’s worth about even. I also bought it because it was a near twin to the one I had over 30years ago and I have no intentions of selling it.