Unfortunately the discs on the Z4M can't be machined as they are floating discs. Any side pressure on the disc will cause it to move around on the float pins that couple the disc to the aluminium hub. One of the reasons these discs are so expensive is due to the floating construction.teamemmenracing said:Might just do that and dress the discs that are on the car, its an hours job at most when you have the tools.