Why on God's Green Earth do you think you need 11.7 in rear rotors? That's DUMB. How big are the pistons on those calipers?
ETA OK I see it now. Yeah, your rear brakes are literally as big as the front.
I'm betting those pistons are also ridiculously huge [confirmed], and you can't build any real system pressure because you're moving so much fluid. Something like 70% of your braking occurs from the front, so your brakes need to be sized accordingly. i.e. 70/30 would be 70 percent on the front, and 30% on the rear.
I'm betting your car would stop harder AND faster with smaller rear brakes. Think about how insanely small a wheel cylinder is compared to a front brake piston. With the setup you have, you're sending half the braking force to the wrong end. I'm amazed that car doesn't swap ends every time you stab the pedal.
One of these days I think you guys will realize that just because Dr. Diff (or anyone else) sells it, doesn't mean Dr. Customer needs to buy it.
