Pre-96 were not restricted but not all were full powere with YPVS.
After that they become a nightmare to derestrict.
But if you are "tuning it to the max" what difference will the year make.
Ultimately they all run very similar engines.
The newer ones are by far the easiest to derestrict.
But again you will want to at some point get an aftermarket CDI.
These bikes can't be tuned to the standards of the Aprilia RS engines, they simply were never designed that way, but can be tuned to give a noticeable amount of power.
Welcome to the forum
I look forward to seeing what it is you end up buying/doing.