See, I think I would go and drive it first. The way I look at it is, if its got mods already in it, I think that shows the car may have been beaten on(keyword MAY). I mean, its not exactly true, you dont really know, but it just to me its seems logical. But then again, maybe he just decided to upgrade, and doesnt beat the hell out of the car, and then your looking at a few free mods in a sense that you dont have to do yourself. So I'd go drive it, see what it feels like. If it feels pretty good, and nothing seems way out of shape, definately go with the 4v.
Besides, if you tell someone you have a Cobra, and someone who knows their cobras that its Atlantic Blue, your gonna get more props for that than the Gt i would think.