Proteo Red is a bit less metallic than Rubino (which happens to be a rubbish colour for the 159 - good thing that the press cars were that colour..!), both are much darker than the 8C colour. I read in the Danish Alfa Romeo Club magazine that the 8C Rosso were used on a batch of show cars on a recent exhibition and that it was -very- expensive... I'll try to dig the magazine up later today.
Proteo 155:
Rubino 159:
8C Rosso:
