> Because if you get chain timing issues on a 2010 BMW diesel, you ain't repairing that, it's more expensive than a new car.
In the article the guy has 3 whole spare cars for donor parts and he does all the work himself. He’s not paying mechanic rates or even buying new parts (which are no longer available).
The amount of time and effort he’s put into this car is undoubtedly more expensive than buying a new car at this point, unless you count his time and free.
> unless you count his time and free.
Which you generally should, because unless he was going to otherwise be paid for that time there is no actual opportunity cost. The "cost" of one's time is only a meaningful metric inasmuch as one is giving up something which would be more profitable.