Unless your going to take it to the track and do a whole lot of heavy braking, you're wasting money on drilled/slotted rotors. Joined aug 5, 2011 · 27 posts. ACDelco 12679525 Body ASM (W/THROT ACTR) ** Read more Its not a grind or squeal, but as someone here stated, a brushing sound. Drilled slotted rotors noise . Drilled and slotted rotors offer drivers the consistent performance they want without changing the responsiveness of the brake pedal. I recently installed drilled and slotted rotors on my 2010 rtc. Brake fade is the gradual decrease in stopping power of your braking system due to prolonged use. That’s where slotted and drilled rotors come in. The brake performance dimpled and slotted brake kit is engineered to give incredible stopping power over factory rotors while reducing heat, noise, pad fade and brake dust. The transfer layer on the rotors surface is typically invisible in all but extreme cases. #2 · may 5, 2008. 2018 porsche 911 gt3 drilled bra...