u can string metal(acoustic) strings on a classical guitar but not the other way round. however, even if u do so, the tension acoustic strings has is more than classical strings, u'll be slowly killing the neck joint, the tuners, the saddles might get pulled off...
classical guitars has shorter, wider frets and has a lesser number of frets i think...classical guitar is all about tone and sound, it usually will not have a cutaway...u wouldnt wanna use a pick on the classical guitar, would sound funny...