Have to say I'm somewhat miffed at that last one.
I figured it must be a Dodge Magnum and a Vauxhall Magnum at least a week ago, but no amount of comparison with your picture and a Vauxhall Magnum could convince me that that was a Vauxhall Magnum.
Look at the picture below, and I have also included a picture of the Vauxhall Firenza (which used the same lights) and your picture to show they are not the same! The Magnum lights are all right-angles except at the outer bottom, quite unlike your puzzle photo which is curved at the inner top.
Incidentally only the Vauxhall Magnum Sportshatch used that shovel-front with those lights; the Vauxhall Magnum itself used the same bluff front with 4 round headlights as the Vauxhall Viva!
There WAS a Vauxhall Droopsnoot prototype which is perhaps the same as your photo, but that is not a Vauxhall Magnum which came quite a bit later...