I've forgotten a lot about the SM, but I do remember it was the hottest thing out of France, and the rest of the world too for it's time. Do you think parts would be a nightmare?
Wasn't it featured in a Bond film or something like it in it's day. I saw a limo version once in Britanny in 1975.
I suppose you've seen this site:
http://www.citroensm.net/