Our Sport Performance, Stage I, Stage II utilize OEM size 2004 STi brake rotors. We use the OEM STi rotors with custom curved slots that match the Wilwood Superlite pad dimensions. Our replacement rotors are 4000 series high quality, high carbon rotors which will significantly outperform and outlast original BRZ/FRS rotors. Please note that slotting pattern may be different from the one shown on the product photo. Additional brake rotor features: