I had a similar problem where the driver side wheel would shudder badly under hard breaking at the track. When i did the SPL bearing swap i had to pull my rotors off and the inside of both rotors had burn in deposits in the shape of the pad. I used some break clean and steel wool to clean the deposits off and the are back to being smooth a silk. Apparently after a session i sat with the breaks applied No No that i know is not ideal. I would check that first then maybe get them turned or replaced.
