Here's my opinion:
I personally would not turbo any engine that was not designed for it.
Though there have been lots of people who have put a turbo on a 2H and are happy with it.
But, factory turbo engines such as the 13BT and the 12HT have much heavier components than their non-turbo counterparts the 3B and 2H.
I own a 1985 HJ60 and wouldn't really recommend it for 21st century traffic. It cannot maintain its speed very well going uphill, and overtaking is near impossible, and it gets up to speed pretty slowly too.
I'd wait for an HJ61, with a factory turbo 12HT.
And as for reliability of the 2H. Some say their lifespan is modest, others say it can go into 7 figures.
But there isn't much concrete evidence either way. Just lots of wishful thinking and hearsay.
End of opinion.