THE convertible Mustang portrays a different image to the coupe and, like most soft-tops, looks at its best with the roof lowered. The glass rear window is a bonus. From the window-line down, however, it duplicates the coupe, with the dummy side scoops and long-bonnet look - although it misses out on the bootlid spoiler. As with the coupe, the main visual problem is the large gap around the wheel arches and the tendency to look short on wheelbase and long on overhang - particularly at the front.