Ok, now that 14" Brembos are in, I pulled the trigger on a bracket that allows me to run the '13 GT500 13.8 rear rotors with my stock calipers. I did it mostly for looks because the 11.8 oem ones looked ridiculous but now that I get to thinking, the larger diameter rotors will apply more torque even with the puny one piston calipers. Should I get an adustable proportioning valve in case the rears start to lock up? I'll be running 285/35 all around, if they ever finish arriving. In case I do need the proprtioning valve, which is a good one?

 

Don't worry about it until the need arises. I doubt you will need one.

 

You were right, went to track yesterday. Car is totally fine in relation to brakes, no lockup or ABS intervention at all.