Not a lot tbh, I use el cheapo discs, about £40 a pair, and drill them myself, they do the job, don't seem particularly warp prone.
Micro cracking is very normal, in the past I've had discs split, but have now found the knack of where to drill, never had a split one since.
Pad material is a lot more important, and correct bedding in, as the pad deposits some of it's material onto the disc to start with.
EBC come with a break in coating that works phenominally well, can use just as normal straight away whilst the coating preps the disc surface.
AP are no doubt supplied with DS2500 pads, as they gave the best deal on a bulk order, nothing more!!
Ebc yellowstuff and bluestuff are police approved for it's repsonse cars, and used almost exclusively, not a single DS pad is.
tabetha
tabetha