Thanks for the insight. I don’t have as many miles as you, but also no warpage issues on the original cast front disks.
My comment was aimed at clarifying the question about carbon fiber disks, which are a very different thing, and high carbon steel disks (vs cast iron) which are comparable and can use the same pads with similar braking results.
As with anything, quality is in the details. Cast iron disks are great in terms of cost, noise properties (they self deaden noise a little bit) and are easy to cast. The problem is that high speed production often leaves residual stresses in the finished product. So, when you get them cherry red, they want to move (warp) back to their relaxed position. Better quality ones would be post heat treated to relieve this stress, then machined. The casting and cooling process is also slowed down to reduce the amount of residual stress. That is how some OEMs do and some do not have warpage issues. Just a little FYI.