FWIW, I looked at the pic before I read your post, and my first thought was, "That's not the right color blue. Too dark. Maybe another color from the cab would look better." Then I read your post, and now I see it's not the color you wanted.
Do the purple and make the switch. You'll be second guessing the entire time you have the game if you don't, and I think purple would accent the cab better.