My Low mileage S3 engine which had been stood for a few years developed a leak on the Crank seal which was/is supposed to be a life time seal.. right t**t to change. but we did it
Its believed that the reason for its fail was down to the engine been out of use for so long then soon as heat been put back into it, jobs f**ked basically

All the seals on it have now been changed as we have re built the whole engine when we did the Forged internals and bigger turbo upgrade
My take on it is this, if the car is driven frequently (even low miles) i don't see a problem with low mle cars, its just when they dont turn a wheel for a given amount of time
As for your car tweed, i l;ike what you have done with it (id have done same as you) and yeah u could return to standard but its now been messed about with. i think some of its originality has now been lost forever. but thats just my opinion.
That said, it would take somebody with a good knowledge to know though if you did return to standard
