If I had a bare shell Fulvia I think that is one of my favourite combinations - the dark red with the Torino stripes and blue and yellow HF stickers. It's kind of subdued but a bit menacing at the same time. That's if I wanted to have some Lancia connection. If not, I reckon Aston Zagato metallic racing green would be very tempting. When mine was painted several years ago I went with the colour it already was, Rosso Corsa, as it wasn't a full spray and I didn't want to open the bonnet and see a different coloured engine bay. I must admit it must be hard to have a bare shell and thousands of beautiful colours to choose from. The great thing about Fulvias is that you can paint them grey, blue etc and they look elegant and you can drive them wearing a suit and tie, or you can go for reds, oranges etc and they look like rally cars. You'll have to decide what look you want and that will narrow it down to just a few thousand!. I would think Ferrari Giallo Fly yellow might look pretty good especially if you are having it bumperless etc.
I want the maroon in the last photo really , saw a 1.2or 1.3 HF in Turin in this colour, pretty sure it was a Dutch car and just fell in love with it, looked absolutely stunning, its not as brown as rosso York so if anyone can help with the colour name or paint code I'd be very grateful