I have worked with 2 sets, one said Zeus and one did not, the zeus one was nice casting quality as far as texture porosity and core shift, the other one looked terible and the guides were not centered in the port and you could see bubbles in the aluminum(it did not cause any running problems once installed). The ports are very small and funky shaped at the entrance, the new guides they put in are loose and needed to be replaced on both sets. After everything was sorted out they were nice but they needed porting and machine work to be any better than a magnum or 308.