Re paint colours, Im not a purist by any means, but I think bold modern colours on a sud dont work all that well. Here in Adelaide there was a Sud getting around that was a bold bronze colour from the locally made Commodore, somehow it never looked right to me. Also when I was choosing colours for my car I tried several reds and found that brighter Ferrari type reds when on the car tended to look out of place. I came across Alfa Rosso 555, which is a deep rich red and has a slight orange hue, which suits the style lines of the car, slightly different from AR 130 that is found on Suds. (Aside - one thing to look out for when choosing a red is that there are blue reds and orange reds and not always do both suit a car.)
Colours that i think suit a Sud from a design perspective - red, blood orange, silver, dark blue, dark grey or black. A metallic with a small fleck in any of the normally 'solid' colours could look stunning. Also be aware that the darker the colour the more time you should spend bodyworking as any imperfections will be highlighted and style lines should be made crisp so they don't get lost.
Hope this helps somewhat..
Josh.