Looking at Morgan classics for me is evocative of memories of movies from yesteryear where things are either monochrome or certainly very solid. When remembering cars of old I don't think I ever remember seeing them metallic. This comes into play sub-consciously when a car choice or preference flags an alert. I do remember as a young teenager in the early seventies seeing my first (already established) candy apple red and Ivory american car. This then introduced my mind and expectations to the possibilities of all things metallic. (Some of you will remember the beautiful burnt oranges and golds of metallic Japanese motorcycles of the early seventies .. K6 Hondas and Burgundy Yamaha YDS7s etc) My preferences are for the base flat colours in a classic shape but I think that's a choice my tertiary values rather than tertiary colours have made for me.
I'm loving the colour combinations used with the M3W and I think, as others have said, that the shape of any car is crucial as to whether it's complimented or flattened by the paint. I'm very fond of the new 'denim' colours used by other companies and a 'stealth black' Aero would look amazing. For the classics though I think my blue (similar to Robbie) works well for the car and was my first choice. Yes there's a metallic sheen in it but quite understated.
This is a great topic and I find that the more it's explored, the more folks seem to revert back to historic colour trends. Great post Simon! Thanks for the topic.