The Contax cameras aren't dressed-up Yashicas. Most of the models don't have equivalent Yashica models.
That said, the reason you buy a Contax is for the Carl Zeiss lenses and not for the bodies. And you either believe that the lenses are a notch above what others offer, or you don't.
By the way, nearly all of the cameras will need to have new foam seals (but that's true of any Japanese camera from the 1980s or earlier), and many Contax cameras (and certain Yashicas) will neeed to have new body coverings.