As bigwinn said, go for Febi, Bosch, Brembo or ATE discs as when you take to the track you shouldn't have to worry about them warping. You have two options as I see it for pads which is run 2 sets, one for road and one for track or run one set that is slightly more aggressive than a road set. I'd advise the latter as its easier and cheaper.
Typically the go to pads for fast road/occasional track use are Ferodo DS2500, EBC Yellowstuff or Bluestuff (which are now R90 approved for the Z4). I tend to prefer a more aggressive pad and live with the squealing on the road (I use Carbotech XP8 or XP10, but Pagid RS29 are also a great brake pad).