Last I looked on NAPA's site, they had two versions of Cobra rotors - the $46 "premium" and the $73 "ultra premium." So which version are we talking about here? I need some rotors and would prefer the local option.I'm certainly not some speed racer, but I do put my car through a few rotor heat cycles. Not just on Mustangs, i've had great luck with the "Lifetime warranty" rotors from Napa/Advance Auto. I think Cobra rotors are like 28-30$ each.
If this cracking is from "track duty" I have a couple of suggestions:Cracking all the way through from the edge to the center.