Adapts 4 piston, Z32 twin turbo aluminum calipers to E46M3 325x28mm rotors on all E36 and E46 non-M front knuckles. 330i/ci knuckles and rotors work directly without needing to buy M rotors. CNC aluminum with gold anodizing, laser logos and 12.9 grade hardware. INSTALL NOTES: The knuckle ear up in the center of the caliper must be ground down flush with the caliper bracket to clear the caliper. In most (Non-M) models, Top hex bolt head (E36M3 socket cap head) is on the inside if the caliper to clear near the brake pads while that nut for that one bolt goes on the outside of the caliper. E36M3 only, needs additional grinding on the aluminum caliper for the socket cap head screw, interference shown in the gallery's section cutaway view. Look at the gallery diagram for wheel fitment. The caliper logo (orange point) is closest to the spokes. While the yellow point is closest to the inner wheel barrel. Use the measurements to compare with your own wheel if you remove it from the car, lay it face down and measure the same points distance from the center of the wheel mounting surface. Pair with our reproduction calipers. Adapt to the brake lines in the car by adding to cart the lines and fittings set we sell separately, E3646FKCLF.