I just came upon this one recently ... Arii Porsche 924 Turbo. The side body, especially windows, proportions are way out of whack. Instead of a low sleek missile it looks like one of us pot bellied modelers! Below is a photo with the Arii on top and a properly done Monogram 924 below.
It's too bad about the body because other parts, like front and rear fascias are done really well.