How much does your car weigh? Plavan has a seriously light, fast car with 2.5L and he runs the S brakes (similar to SC size, with lighter aluminum alloy front calipers) with Raybestos ST43 pads. Always says he's got no desire for more/bigger brakes.
Cooling and pads are key. Do the best you can to get air ducted to the rotors with hose (smooth/straight with minimal bends is important) and seal off the rotors to get the cooling air into the eye of the rotor and out thru the cooling vanes. Block off the gaps in the hub with these star plates or make your own.
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Use true dedicated race pads that can handle the heat. You can also use tricks like titanium "shims" between the pads and pistons to reduce heat transfer into the fluid.
Racers Edge Porsche Suspension Yeah I know those don't fit your Carrera pads but you get the idea.