JCW Brembo front caliper brake piston is made of a synthetic material (not steel) which I heard on extreme cases can get deformed. I am planning to upgrade my brakes to JCW but dont want to run on those issues.
Does anybody know the piston size on front calipers JCW Brembo (4 piston) 38x26? I am looking for SS replacement so it can solve the issue.

 

I haven't heard of this problem and my car has been rocking the JCW brake kit for six months

 

I read that online and heard from some vendors as I am looking to upgrade my brakes. The JCW caliper pistons are made of composite material (not steel) under extreme temperatures they warp and deform. I actually found some pictures online is really bad. Obviously depends on the track, tire, driver skills, etc .... most likely the reason not everybody is experiencing the issue.
As I know I am typically very hard to brakes want to assure a solution is available so I can resolve the problem before it shows up. In case I cannot find a solution the next option would be to get Wilwood.