Even though they say the original Konis, (and the adjustable Ariston‘s) are rebuildable by Koni, I have not seen too many people who have had it done successfully.
if you’re over here in the USA, a couple of the vendors have spring and shock packages. That would be Dennis Quella Pantera Performance, Castle Rock) and Scott Bell (SACC)
Probably most of the other vendors as well! They are already set up for the ride, ride height, and spring rides.
(As a note, Scott Bell used to take the original shocks in as trade-ins. Maybe he has a good set. I have a set of them up in my attic. They are very heavy. It will cost a lot of money to ship overseas).