they are two piece floating roters with an aluminum hub hat and an iron disk, they replace the entire disc unit at one time.
however a lot of vibrations from the track are not always due to warping but due to brake pad material melting to the rotor. if so it will wear off and go away after a few thou miles, the only way to tell is to but the brake rotors on a lathe.
two pc. rotors should resist warping better than a one peice rotor (a single pieceof iron, hub and disc. )