My previous E92 had 53000 kms and 3 full seasons of track issues with no real issues due to track use.
Power steering:Minor fluid leak out the cap.The only time I had a real issue I was on Hoosier slicks and the steering lost assist and was very noisy but was fine when it cooled down.The slicks were another issue and only lasted 45 minutes of lapping but were very fast!
Brakes: I've gotten them nice and toasty but they are still working for me with proper pads.Orginal rotors lasted the full 3 years still being above the wear limits.Went with a Stoptech 380mm on the new car.
Engine: 53000 kms and no issues.Usually did not need any oil added between 12000 km oil changes.
Bushings & Subframe: No issues.