They do rot badly, from the inside out, so a car that can look mint can be anything but! The rear chassis rails are a common place.
I sold my VI a couple of years ago, but I seem to recall some tuners were starting to stick cameras into the bodywork to check for internal rot.
They are hero cars - I loved mine. It was reliable, but it was always in the back of my mind that if it did break, it was $$ time. That plus the fuel consumption, plus the fact that every Tom, Dick, and Chavvy tries it on with you does put you off a bit.
Here's my old one:
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