Metallic reds, greens (albeit acceptable on a Jaguar) and unusual metallic hues such as gold or brown are very much a "bespoke" choice. By this I mean that you might find someone willing to buy the cars and pay the average trade price, but it is more likely that these cars will take much longer to sell and for some of these colours at a considerable discount to trade values. There are some occasions when unusual colours are well received, Mini springs to mind, but also, on the right Motorsport related car such as an RS4, R8 or an M3, where oranges and Sky blues will find a buyer, as the colour suits the type of buyer and product more closely.