I been searching but only finding the difference in weight and compression. I would like to know which one of the 2 is the strongest or are they equal in strength?

 

As far as I'm aware, the s4 NA rotors have the thickest casting on the rotor faces of any series. This is beneficial in case of severe detonation, it will reduce the chance of denting the rotor itself.

That's why I went with them on my build.

 

That's kind of odd, given that they are the same weight as the T2 rotors. Wonder how much thicker they really are.