This is a bolt on front brake kit, which works with your existing factory single thickness rotors. Using Wilwood’s ultra-lightweight forged aluminum 4-piston calipers (which are nearly 4 lbs lighter per caliper than stock units), modern friction compounds, and custom-fit hard lines. The pads supplied in the kit are a versatile compound with great street manners and tolerance of occasional track use and aggressive canyon driving. Optional more aggressive track specific compounds are available, contact us.