I can back that up - if you assemble the wheel to the shaft in the same 'clocking' that it was, you haven't affected the balance so it'll be ok (if it was to begin with of course)

You can actually get rebuild kits for them and diy it - unless it's damaged the shaft in which case it might need to be polished/turned down and oversize (or is that technically undersize) bush/bearings utilised.

Anther quick tip - when starting the motor for the first time, pump oil with an oil can into the turbo, then hold the compressor wheel (*gently of course) with air intake off, whilst someone else cranks the motor over with the plugs out, do it with a slightly cracked open oil feed pipe to the turbo, and have them do this until oil starts to flow out the pipe/flange, then re-tighten, fit plugs and proceed. I'd go a little further and suggest pumping a little oil into the turbo centre as soon as you get it, as speaking for myself - any turbo I have on a bench, every man and his dog picks the damn thing up and twirls the compressor around!

It _is_ actually possible the turbo was ok as far as the seller knew. If the last time it was shut down, it was shutdown hot, or some other unforseen issue, then it might have lead to coking of the oil still in the turbo centre/bearing area, and it ran fine right up until then.

Generally speaking, as much of an extra headache as it is, I always buy s/hand turbos on the basis they 'are' stuffed and pay accordingly. That way if they turn out ok, bonus, if not, well I haven't dropped a lot of money on them, and the money saved will cover a rebuild.