GM has X # of brembo setups they are under contract for, but also had a performance feature that could be implemented with minimal additional cost; so it came down to a simple $$ decision.
Do I think a bigger rotor is needed just for torque vectoring? No. I do like TV but have only flogged AWD cars that had that feature standard around the track. It helps a lot with an AWD to get the car rotated, normally you tend to plow/understeer with an AWD, without unsettling the car with throttle on/off.
I know it would be a very very very small number of owners, but has anyone with a strange or other non-oem setup noticed any substantially difference in braking performance? For things like TV, brake fade, stopping distance, rear lockup, etc.?
Anyone removed the rear rotor, to get them turned, and thought it was an exceptional pain in the ass?