I only know one source for 360 suspension parts, it's this place in the UK
https://www.classicswede.org.uk/Polyurathane_bushes_3_series/cat1733345_1580905.aspx
360 parts availability is hit and miss generally, performance parts are easier to get hold of.
Also, welcome, and I hope you enjoy your 360, I had a clapped out 360 a while back and it was a lot of fun to drive, it wants to be hammered.