Middly, you are going to be quite disappointed with your brake setup! 1/4 mile runs will not produce enough surface gases on the rotor face to merit the use of cross-drilled or slotted rotors. I can see if you were on the track, where the constant application of your brakes would get things hot enough to experience gas-fade but this would not occur on the drag strip!! Another issue to consider is your choice of PosiQuiet Semi-Metallic pads. The Posi's have the exact same temperature threshold as the OE pad compound used by TRW, Pagid and Jurid; the vendors who manufacturer stock pads for our BMW's.
This setup will not improve your braking at all on a drag strip! The rotors will look very nice, but your stopping distances will not improve with the driving scenarios you described. Instead of the PosiQuiet pads, you might want to try a slightly more aggressive brake compound. Not many companies have pads for our cars but EBC has Green/Yellow/Red compound pads which will give you better bite on those new slotted rotors. I would go with the Greenstuff pads because the blended compound will provide better stopping in the winter months over a set of full ceramic or track pads!
Now if you want to spend the $$$$$, check out the Brembo Kit from Turner Motorsports. I would also check to see if BMW makes M-Performance brake upgrade available for our cars.
Good luck,
Will aka The Swami
