AA, I would say if you can pick up the original at a fair price then go for it. If it doesn't match your aspirations, shouldn't have any problems re-selling on.
As I've mentioned many times the Nait 5i was scarily powerful for 50 watts (depending on speaker dbs), more, I'd guess, in the region of 70-80 watts. If the Uniti (MKI) mirrors the Nait 5i - and you have a normal sized room - there shouldn't be a problem.
However, the main caveat (as mentioned in your previous threads), the Uniti probably won't give you the overall SQ of your Monoblocs.
The only way to know for sure is to make the effort and purchase the Uniti (if you can't dem one), and see how it stacks up against the Audiolabs.
Good luck, pp